Alcatraz

What is it: Alcatraz is an island situated 1.25 miles from San Francisco that became famous as a prison. Because of the dangerous currents between the two, it was used to house some of the USA's most notorious criminals (Al Capone was in there for a while). It is claimed that no prisoner successfully escaped from Alcatraz in 29 years, although quite a few tried: 23 were caught, six were shot and killed during their escape, two drowned, and five listed as "missing, presumed drowned". It was closed in 1963. 
What's it like: The audio tour is probably the best one that I've ever done - I highly recommend it. It brings the whole thing to life. 
Where: San Francisco, USA
When: April 2015
How: We did a road trip from San Diego up to San Francisco. We also visited the Golden Gate Bridge (60) and Yosemite National Park (20). Alcatraz is a short boat ride from Fisherman's Wharf in San Francisco.

Worth noting: There was an ex-prisoner signing books when we were there.
Place in the 2015 version: 228 
Did it deserve to lose its place in the 2020 top 500: Pete would have been furious that Alcatraz lost its place - he'd have put it in the top 100. 

Alcatraz