500 Places to Take Your Kids Before They Grow Up highlights 500 of the most exciting and memorable cities, museums, and trips throughout the world. The destinations below are six of the best ways your entire family can have an out-of-this-world experience without leaving the ground.

What: Greenwich: Where Time Begins
Who: Ages 8 & up
Where: England

It's one of those classic photo ops: Standing astride the Greenwich Line, 0° 0' 0" longitude, the point from which since 1884 all terrestrial longitudes around the globe are calculated. Tell your children they're standing on the dividing line between the Eastern and Western hemispheres; if they were here at the stroke of midnight, they could have one foot in 2 different days, for by official world decree a new day begins at the Greenwich Line.

The red-brick house on the hill was designed by a then-unknown architect, Sir Christopher Wren (himself a passionate amateur astronomer), who won the commission from Charles II in 1675. The king's motives were quite practical: Improvements in astronomy would lead to better navigation techniques, which would help Britain dominate the seven seas. (And, no surprise, it worked out exactly the way he'd hoped.) Wren's el-egant Octagon Room was the observatory used by the first Astronomer Royal, John Flamsteed; unfortunately, because it wasn't properly aligned with celestial meridians, it was useless for observation -- a fact no one bothered to tell the king -- and telescopes were surreptitiously installed in a shed in the garden instead. As the years passed, uniform timekeeping became more and more important, especially to regulate railway schedules. The synchronized clocks of Victorian England eventually became a model for the rest of the world, and just as all distances were calculated from Greenwich, so was Greenwich Time established as the world standard. In this respect at least, England will always remain the center of the world.

Although the Royal Observatory is no longer a working observatory -- light pollution from the metropolis forced a move in the 1940s -- it does have galleries full of historic stargazing and timekeeping instruments (including England's largest refracting telescope, a 28-in. lens, and a rare camera obscura), which children will find of varying interest. But be sure to go out onto the roof, where there is a spectacular panorama of London, especially the nearby skyscrapers of Canary Wharf. Look up to see the red Time Ball, which slides down its mast every day at 13.00 hours -- the world's first public time-indicating device.

Frequent ferryboats from either Charing Cross Pier or Tower Pier run every half-hour or so to Greenwich, taking about an hour; the train trip from Waterloo Station is faster, about 15 minutes, but less atmospheric.

Contact: The Royal Observatory, Greenwich Park (tel. 020/8312-6608;

What: Stargazing on Nantucket
Who: Ages 6 & up
Where: Massachusetts, USA

Though her fame has sadly faded, Nantucket native Maria Mitchell (1818-89) was quite possibly the most famous American scientist of the 19th century, man or woman. In October 1847, on the rooftop of her family home, this self-educated 29-year-old trained her telescope on the night sky and became the first person ever to record a sighting of a comet that was invisible to the naked eye, an accomplishment that vaulted her to international honor.

On Nantucket Mitchell is remembered at a complex of science centers. Your first stop should be on the southwest edge of Nantucket Town at Maria's birthplace, the Mitchell House, 1 Vestal St. (tel. 508/228-2896), a modest Quaker home built in 1790. It was turned into a museum soon after Mitchell's death by her former students and colleagues and contains many family artifacts, including her own telescope. Take time to wander through its wildflower and herb gardens. The nearby Hinchman House Natural Science Museum, 7 Milk St. (tel. 508/228-0898), expands Mitchell's passion for observation beyond astronomy; yes, there are exhibits about Nantucket flora and fauna, but there's also a raft of activities, like bird-watching, wildflower walks, and hands-on discovery classes for both children and adults. Dissecting an owl pellet can be fascinating. Over on the harborfront, the Maria Mitchell Association's aquarium, 28 Washington St. (tel. 508/228-5387), is small but very kid-friendly, focusing on the local marine ecology.

It's only fitting that, because of Maria Mitchell, this tiny island has not one but two observatories, and if the night sky is clear, don't pass up the opportunity to stargaze here, far from the light pollution that frustrates astronomers in big cities. Out on a hill south of town, Loines Observatory, 59 Milk St. Extension (tel. 508/228-8690), is open to the public every clear Monday, Wednesday, and Friday night in summer at 9pm (rest of the year Fri 8pm); if there's an interesting sky event, like the close orbit of Mars the summer we visited, the line may be out the door. The Vestal Street Observatory in town at 3 Vestal St. (tel. 508/228-9273), where Maria and her astronomer father swept the skies in the 19th century, is too close to town for nighttime stargazing, but tours every day at 11am show off a good exhibit on the science of astronomy. Don't miss the outdoor scale model of the solar system.

Contact: The Maria Mitchell Association, 4 Vestal St. (tel. 508/228-9198;
Season: Early June to late Aug.

What: Greenwich: Griffith Observatory: Planetarium Hollywood
Who: Ages 6 & up
Where: Los Angeles, California

Film buffs instantly recognize this streamlined Art Deco observatory in L.A.'s rambling Griffith Park from the climactic scenes of the 1955 James Dean classic film Rebel Without a Cause. My kids, however, know it from the climactic scenes of the 1999 Steve Martin-Eddie Murphy comedy Bowfinger. But so what if they don't get the Rebel Without a Cause reference? Who could fail to dig this white stucco complex with its three bronze domes, slung into the south side of Mount Hollywood with a killer panorama of Los Angeles spread out below? In the daytime, the lawn of the observatory is one of the best places in the city to view the famous Hollywood sign; on warm nights, with the lights twinkling below, the Griffith Observatory's wide terrace is one of the most romantic places in L.A. And if you manage to steer the children inside to do a little stargazing while you're up there at night, you're ahead of the game.

This Hollywood Hills landmark was built in 1935 in the vaguely Mediterranean style studio moguls of that era favored, and underwent a major renovation during 2003-06. A white obelisk in front honors six great astronomers of the past: Hipparchus, Copernicus, Galileo, Kepler, Newton, and Herschel. The large central dome houses a state-of-the-art planetarium, where narrated projectors display the stars and planets that are nearly impossible to observe outdoors, what with all the smog and light pollution of the L.A. metro sprawl. Like most planetariums, it also screens various multimedia shows of varying scientific seriousness. We generally skip the planetarium, however, and head straight into the adjacent Hall of Science, which holds exhibits on galaxies, meteorites, and other astronomical subjects -- cool objects like a mechanical orrery, a Tesla coil, and scales where you can check your weight on different planets. A Foucault pendulum mesmerized my boys as it methodically swung in the main rotunda, demonstrating the earth's rotation, and detailed 6-foot topographical models of the earth and the moon provide focal points in the side galleries.

The observatory's two flanking domes each house a telescope -- in the west one, a triple-beamed solar telescope trained on the sun for daytime visitors, in the east one a 12-inch refracting telescope. On clear nights visitors can climb to the roof and wait their turn to gaze through it at the moon and planets. This is, after all, an observatory, and although it has never had the astronomical prestige of its California neighbor Mount Palomar , it does attend to sky matters.

Contact: Griffith Park (tel. 323/664-1191;

What: Mount Palomar: Where Stars Shine over the Desert
Who: Ages 8 & up
Where: Mount Palomar, California

In July 2005, the world was startled to learn that a 10th planet had been found orbiting our sun (just after my sixth grader got an A for his model of the solar system -- a model that's now obsolete). And where was that astonishing observation made? At Mount Palomar, California, where Cal Tech astronomers have been making scientific headlines since 1949.

This mountaintop in San Diego County was purchased in 1934 because light pollution from the fast-growing Los Angeles metropolis had become a problem for Cal Tech's former observatory, atop Mount Wilson in Pasadena. For the new site, Mount Wilson's 100-inch telescope -- through which Edwin Hubble had studied distant galaxies to prove the universe is expanding -- was to be outdone with a 200-inch reflecting telescope. A Depression-era American public eagerly tracked the progress of this grandiose plan. At first, no one could build a stable lens that big -- until the Corning Glass company made one using its new heat-resistant Pyrex glass. The immense glass blank was carefully shipped cross-country, then was ground and polished for a couple of years. Meanwhile, other parts for the telescope had to be made in shipyards, the only workshops geared to manufacture parts that big (which explains the battleship-gray hue of the scope's housings). After a 5-year hiatus during World War II, the telescope was finally ready to assemble in 1947.

Dedicated in 1948, the Mount Palomar telescope was the world's largest until 1976 (when an even-larger Soviet model debuted). Today, visitors can stand on the gallery surrounding the 200-inch Hale telescope to see the big instrument, but be prepared -- the dome is kept at a steady temperature calibrated to nighttime temperatures on this mountain, so you'll need a sweatshirt or jacket even in summer. To get the full scoop, come on a Saturday for an hour-long explanatory tour (book a week ahead). Astronomical photos and other exhibits are displayed in an outer gallery, but nothing as extensive as the ones at Griffith Observatory down in Los Angeles.

My kids were baffled by the back-roads trek it took to get here, until we explained that isolation is good for astronomy. They were surprised when they saw the small, simple facility beneath that serene-looking dome in a mountain meadow. But the size of the Hale telescope, and the quiet hum of serious science going on, gradually began to impress them. They no longer felt like tourists -- they felt like hardy explorers in pursuit of knowledge.

Contact: Mount Palomar (tel. 626/395-4033;

What: Mauna Kea: Stargazing at the Top of the World
Who: Ages 13 & up (summit), 10 & up (visitor center)
Where: Hawaii, USA

The snowcapped summit of Mauna Kea -- the world's tallest mountain, if measured from its base on the ocean floor -- is the best place on earth for astronomical observation. It's not just the height, it's also its location near the equator, where clear, pollution-free skies give way to pitch-black nights undisturbed by urban light. That's why Mauna Kea is home to no fewer than 13 world-class telescopes, including the Keck Telescope, the world's largest. Even with the naked eye, the stargazing from here is fantastic.

Many tours that go to the summit won't take anyone under 16 or any pregnant women, due to the high altitude. If you opt not to go up, it's still cool to view the model of the Keck Telescope down in Waimea, 65-1120 Mamalahoa Hwy. (tel. 808/885-7887; Developed by the University of California and the California Institute of Technology, the Keck is an infrared telescope eight stories high, weighing 150 tons, and with a 33-foot-diameter mirror made of 36 perfectly attuned hexagon mirrors -- like a fly's eye -- rather than one conventional lens.

You'll need a four-wheel-drive vehicle if you do drive up the mountain. The Onizuka Visitor Center, named after a Hawaiian astronaut who died in the Challenger explosion, is an hour's drive from Hilo or Waimea; from Highway 190, take the narrow, rutted Saddle Road (Hwy. 200) 28 miles, then turn onto unmarked Summit Road and go another 6¼ miles to the visitor center. At this point you're already 9,000 feet up, so stop for half an hour to acclimate. With younger kids, this may be your endpoint, so time your visit to join the nighttime stargazing sessions, 6 to 10pm, which include a lecture, a video, and the chance to peer through 11-inch, 14-inch, and 16-inch telescopes.

It's 6 miles from here to the summit, but it can take 45 minutes to drive this rough, unpaved, winding road, in low gear all the way -- a climb of another 4,200 feet -- to 13,796-foot-high Observatory Hill. Dress warmly and drink lots of liquid; wear dark glasses to avoid snow blindness, and use plenty of sunscreen. At the top, 11 nations, including the U.S., Japan, the U.K., France, and Australia, have set up 13 powerful infrared telescopes to look into deep space. On this bare peak, their bulbous pale domes sprout around a loop of road like alien spacecraft plopped down on the moon. Visitors can't use those telescopes, of course, though you can look at a couple (including the Keck) from galleries. (They won't be active until night, anyway.) If you take a narrow footpath past the observatories, however, there's a cairn of rocks where you can sit and contemplate an incredible 360-degree view across the Pacific. Even if you're socked in by clouds, it's a true top-of-the-world view, with the summits of Mauna Loa and Maui's Haleakala poking through the puffy white cumulus clouds beneath your feet.

Contact: Mauna Kea (tel. 808/961-2180;

What: Norwegian Polar Nights & Northern Lights
Who: Ages 6 & up
Where: Tromsø, Norway

Just about every attraction in Tromsø, Norway, bills itself as the "world's northernmost" this or that -- the northernmost university, the northernmost cathedral, the northernmost golf course, the northernmost brewery. What else would you expect of a city 400km (250 miles) north of the Arctic Circle? But for sky watchers, Tromsø's extreme location means great opportunities year-round to observe all sorts of unique phenomena, from the comforts of a city so cosmopolitan it's been nicknamed the Paris of the North.

Let's start with the rarest phenomenon: The Northern Lights, or aurora borealis, created by stray particles from storms on the sun's surface eddying around that big magnet known as the North Pole. On dark, clear nights from about 6pm to 2am, you can see their energy released in wonderful shimmering curtains of light -- in Tromsø, one of the few towns on Earth where the Lights are visible, you can see them even from the city center nightly from October through April. Green is the prevailing color up here, though on good nights the whole spectrum glows. And you do get a lot of nighttime from November 21 to January 21, when the sun never rises above the horizon. Scandinavians put a positive spin on this by calling it Polar Nights, and having star-spangled skies 24-7 truly isn't all bad, especially not when the aurora borealis kicks in. Tromsø is blessed with a surprisingly mild climate, even in winter, so you can get outdoors and enjoy those winter skies; several local tour operators take groups out into the countryside to see them at their most spectacular.

You can't see the Northern Lights from May through August, though, for the simple reason that the sun is always in the way: May 21 to July 21 is the season of the Midnight Sun. It sounds simple, but if you've ever experienced it, it's truly magical, to feel the world kissed with sunshine around the clock. Summertime in Tromsø also offers whale-watching (tel. 77-62-44-40; or roaming around the open-air historic museum, Kvaløyveien 55 (tel. 77-60-19-10), and the university's large Alpine Botanic Garden, full of rare Arctic flora. If you do come here in summer -- which, given school vacations, may well be your time frame -- you don't have to miss the Northern Lights entirely: The Northern Lights Theatre, Prostneset (tel. 92-84-27-13), shows a film of the aurora all summer, and the University Museum of Tromsø has what it calls a Northern Lights Machine to simulate the experience.

Contact: Tourist information office (tel. 77-61-00-00;

This article is an excerpt from 500 Places to Take Your Kids Before They Grow Up, available in our Online Bookstore now. Author Holly Hughes has traveled the globe as an editor and writer -- she's the former executive editor of Fodor's Travel Publications, the series editor of Frommer's Irreverent Guides, and author of Frommer's New York City with Kids. She's also written fiction for middle graders and edits the annual Best Food Writing anthology. New York City makes a convenient jumping-off place for her travels with her three children and husband.

Talk with fellow Frommer's travelers on our Family Travel Message Boards today.