Experience the "top tour in Chicago and one of the top ten tours in the U.S." according toTripAdvisor users. The Chicago Architecture Foundation River Cruise is a must for out-of-towners and Chicagoans alike. CAF-certified volunteer tour guides—called docents—interpret more than 50 buildings along the Chicago River. You'll find out how Chicago grew from a small settlement into one of the world's largest cities in less than 100 years. In 90 minutes, get the real story on Chicago architecture and its history.

See some 1,200 animals, from apes to zebras, at the oldest and one of only a few free zoos left in the country. It is small, only 35 acres, but attractions like the Kovler Lion House and the Regenstein Center for African Apes pack a big punch. The newest feature: The Regenstein Macaque Forest, where snow monkeys swing through trees and relax in a hot tub.

This tourist hot spot features shops, eateries, an IMAX cinema and a bevy of sightseeing boat tours. Pier Park is home to a 150-foot-high Ferris wheel, plus an old-fashioned swing ride and 18-hole mini-golf course. You'll also find the Chicago Children's Museum and a rotating roster of live entertainment on the Family Pavilion Stage. Most offerings may not turn locals on, but the seasonsal events, indoor activities and great people-watching provide plenty of entertainment, no matter what the weather.