Photos: Alfred Twu · CC0 (1, 2, 3, 4) · Cary Bass-Deschenes from San Francisco, United… · CC BY-SA 2.0
A warehouse in Sausalito holding the whole bay and delta at scale, with walkways over it from end to end.
Why it's unique
A walkable 1.5-acre hydraulic model of San Francisco Bay and the Delta, built by the Army Corps of Engineers in 1956 and 1957 after a proposal to dam the bay. It can run a full 24-hour tide cycle in about 15 minutes.
It was funded to test the Reber Plan, a 1940s scheme for freshwater reservoirs that it helped show was unworkable. The claim stops at the country, because "world's largest" comes only from a listing.
Before you go
Phone 415-289-3007 first and ask whether water will be running that day. It has been a teaching display rather than a research lab since 2000, and whether the tide runs on any given day could not be confirmed.
Hours differ on every page: Tuesday to Saturday 9 to 4 in the most reliable source, with one listing closing weekdays at 3. Weekday afternoons without school groups are calmer. Guided tours are for groups of ten or more by reservation; individuals self-guide.
