Hold down the left mouse button, keyboard arrows, or touchscreen then move to navigate in any direction.
Press the + key, mousewheel up, or pinch on touchscreen to zoom in and - key, mousewheel down, pinch to zoom out.
A user-controlled panorama of Union Square in San Francisco.
Have a poke around the square. It wasn't always as nice as what you see. About 14 years ago, the square was a useless walk-through "garden" of sorts with patchy bits of grass and dirt.