Part of the beauty of San Francisco is the fact that you can walk just about everywhere. And considering that the city is a national architectural center — chock-full of Victorian and modern buildings, with skyscrapers brushing elbows with Painted Ladies — there's plenty of eye candy to consider while working your gams. History aficionado Rick Evans is the best repository of information on the buildings that pepper your favorite neighborhoods, and his two-hour, $20 walking tour is the kind of fact-filled excursion you needn't be a tourist to enjoy. His colloquial approach to construction techniques and social history alike will have your head teeming with all kinds of random know-how, such as how a 50,000-gallon water tank can protect a building from an earthquake. You'll explore unique and important downtown spaces (ending at the Transamerica Pyramid) and lollygag in rooftop gardens, swanky hotel lobbies, and unmarked passageways. Sure, office buildings aren't exactly off the beaten path, but Evans has a knack for guiding you through public spaces you scarcely knew existed.