Almost everyone has heard of Alcatraz, in its day the baddest federal prison of all. It is located in the cold waters of San Fransisco Bay. "The Rock" closed as a prison in 1963. Now there are daily tourist excursions. The island is 1.25 mile from San Francisco and the currents are strong. The government claims that no one successfully escaped.
Since I have an iffy sense of balance, paddle boarding escapes me. My son did it on the lake shore of Chicago when he lived there, and still gets out on the lakes of central Michigan where he lives now. I have a friend in New Orleans who paddle boards through the bayous, dodging alligators as she goes. I wouldn't stay upright when the first ripple came by.