The Steam Clock in Gastown is a favorite photo op for tourists, but you're not missing much if you miss it. Built by horologist Raymond Saunders in 1977 (based on an 1875 design), it's the only steam clock in the world, powered by steam from an underground system of pipes that supply heat to many downtown buildings. The clock is supposed to sound its whistles (playing "The Westminster Chimes") every quarter-hour as the steam shoots out from vents at the top. Sometimes, however, it simply steams with no musical accompaniment. It's a stop on my Gastown and Chinatown Walking Tour 2.