Beaches: The St Petersburg beaches are wide and inviting, and according to most beach experts, they are among the best in the country.
Museum of Fine Arts: The elegant Palladian-style building combines the styles of a classic art museum and a Mediterranean villa at home in Florida's tropical climate. The building itself a work of art, has twenty galleries, some small and intimate, others more spacious. The Museum also has splendid Membership and Sculpture Gardens.
Sunken Gardens: Sunken Gardens is a botanical paradise in the midst of a bustling city. As St. Petersburg's oldest living museum, this 100 year old garden is home to some of the oldest tropical plants in the region.
Pier: Of all the St Petersburg attractions that are of the manmade variety, none are more renowned than the Pier. Home to a five story building that features an inverted pyramid design, this city landmark is hard to miss.
Source: http://www.stpete.org/