Ordered to blockade Martinique in 1803, Commodore Sir Samuel Hood covered an island with guns and declared it a sloop-of-war. Perched 175 meters above the sea, the guns denied all entrance to Fort-de-France, the island’s main port, for 17 months.

The British Royal Navy still regards “HMS Diamond Rock” as being in commission — when passing the island, personnel on Royal Navy ships stand at attention and salute the rock.

Since that time, a naval establishment on land has been referred to as a “stone frigate.”