Everything in Beijing is big. Tian'an Men Square is roughly the size of 90 football fields, wandering through the Forbidden City feels like a minimarathon, and of course the Great Wall is . . . very long. It is fitting then that hosting the Olympics in Beijing meant building awe-inspiring, people-dwarfing structures. And all at a sizable price tag of $40 billion.

Beijing's Olympic Green is the main attraction. Wear comfortable shoes, because the green covers an area roughly six times the size of Athens' Olympic Green and three times the size of New York's Central Park. Electric trolleys with tours in Chinese only will take you around the green for ¥20, round-trip. The biggest draw here is the Beijing National Stadium, dubbed "the Bird's Nest" because its oblong shape and interlocking steel grids closely resemble the twigs and branches of, well, a bird's nest. The original design featured an innovative retractable roof, but that was scrapped a year before the XXIX Olympiad due to cost and time pressures. But even without a fancy convertible-like ceiling, the Bird's Nest is an impressive architectural feat. It was designed by architecture darlings Jacques Herzog and Pierre de Meuron, cost roughly $400 million, and can hold 91,000 spectators. It hosted the opening and closing ceremonies, as well as athletics events and football. The ¥50 entrance fee (ticket booths are at the north end of the nest) gets you into the stadium, where you can walk right onto the field and have your picture taken with the Olympic torch for ¥15. A post office on-site sells commemorative stamps and a few other stores sell Olympic kitsch inside. A healthy stone's throw away from the Bird's Nest is the National Aquatics Center, also known as "the Water Cube" (it's actually a rectangle, but "Water Rectangle" didn't have the same ring). From the outside, it looks like a giant cube made up of hundreds of bubbles. Swimming, diving, synchronized swimming, and water polo events were held here. If you've been to a high-school swim meet, save yourself the ¥30 entrance fee, because the indoor view of the Water Cube is pretty much the same. You can swim at the Water Cube, but only in the warm-up pool. Head to the ticket booths on the western side of the aquatics center. The ¥50 entrance ticket buys you 2 hours of swimming in crowded, often chaotic lanes. A mandatory swim test (100m in the stroke of your choice) is required and you must wear a swim cap. North of the Water Cube is the National Indoor Stadium, which hosted gymnastics and handball events. Its design plays on the theme of a traditional Chinese folding fan. Unlike its neighbors, it doesn't have a cutesy nickname.

Behind the Olympic Green is the Olympic Forest Park. During the Olympics, the park hosted tennis, archery, and hockey events. This spacious bit of greenery includes Main Mountain, a man-made pile of 3.98 million cubic meters (141 million cubic ft.) of earth, and Main Lake, a 110-hectare (272-acre, roughly 205 football fields) body of water shaped like the Olympic torch. While this is Beijing's largest city park at 640 hectares (1,581 acres), there's nothing terribly special here. It's over 1km (less than a mile) north of the Water Cube and Bird's Nest, so if your feet are already aching, you can skip this attraction.