Lake Tahoe

Thanks, everyone! Yes, it's a huge lake--biggest alpine lake in North America, second-deepest in the US (after Oregon's Crater Lake), and per Wikipedia it's the 27th largest lake (by volume) in the world. There's a local urban legend that it's in a volcanic crater. This isn't true, as we used to tell the undergrads--it's a downfaulted valley, a so-called graben, that is dammed at the north end by a couple of small shield volcanoes (Mt. Pluto and another that escapes me). The level of the lake was raised about 10 ft in the early 20th century by a dam at the outlet, so it also now acts as a water-storage reservoir.