When construction of City Hall began in 1871, it was to be the tallest structure in the world. But plans were scaled back, other buildings surpassed it, and the elaborate 1901 wedding cake by John McArthur, Jr., with an inner courtyard straight out of a French château, quickly became outdated. The charming building is still in use as the mayor's office and is home to offices from the Register of Wills to city courtrooms to city council's quarters. Philadelphians love the crowning 37-foot statue of William Penn by A. M. Calder. For years, the structure appeared rather rusty and grimy, but now, with repainting, new cast iron work, and cleaning, City Hall has reclaimed its pride.

You may wish to wander inside the vast floors, which range from the breathtaking to the bureaucratically forlorn. Both inside and out, City Hall boasts rich sculptural decoration. The Mayor's Reception Room (no. 202) and the City Council Chamber (no. 400) are especially ornate. A tour of the building itself (not the tower) lasts up to 2 hours.

A rare highlight of your tour is heading up to the observation deck. This attraction being run by, well, functionaries, you're not guaranteed to get up there. Best bet: Call tel. 215/686-2840 the morning of for a timed reservation. Admission is free. Tickets can be picked up in room 121.

The elevator up to Penn statue's recently cleaned shoestrings, at 548 feet, can hold only four people, and the outdoor cupola cannot hold many more. On the way, notice how thick the walls are -- City Hall is the tallest building ever constructed without a skeleton of steel girders, so its white stone is 6 feet thick at the top and 22 feet thick at ground level. The view from the top encompasses not only the city but also the upper and lower Delaware Valley and port, western New Jersey, and suburban Philadelphia. It's windy up there, though. If you look straight down, you can see more of the hundreds of sculptures designed by Calder, the works of whose descendants -- Alexander Stirling Calder (1870-1945) and Alexander Calder (1898-1976) -- beautify Logan Circle and the Philadelphia Museum of Art. You could spend hours, although 45 minutes should do it for the highlights.