One of the most interesting features of the western coast of the San Francisco peninsula is the Sutro Baths, a late 19th-century swimming pool complex that's now a majestic cliff-side ruin. The tumbled remains of the baths are home to a variety of coastal wildlife, and keen-eyed observers may be able to spot grey whales breaching the water nearby. A small but fascinating museum explains the rise and fall of this once-popular location, and has a small cafe from which to admire them.