Is 170 arpents as big as Alcatraz?
It's about six-and-a-half times as big as Alcatraz
The size of Alcatraz is about 26 arpents.
(a.k.a. The Rock) (California)
Alcatraz Island measures 26 arpents. It is known a part of the Golden Gate National Recreation Area, and has historically served as a lighthouse, fort, military prison, and — most famously — a federal prison.
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