Why are Alcatraz Tours so very popular: is it that tours of this fortified island in the San Francisco Bay reveal that it was a military prison before civilians were incarcerated there, or that it once housed the Birdman of Alcatraz and Al Capone, or that it was occupied by a band of ‘Indians of All Tribes’, claiming ownership of the land, for 19 months between 1969 and 1971?

Whatever the reason, tours of the island are often booked out in well in advance. Apart from the grim fascination of its 34-year history as a maximum security penitentiary, the island has completely unique flora and fauna – such as unnamed roses planted by residents and prisoners long gone, and deer mice that have adapted to the concrete environment by evolving a lighter color.

The Alcatraz occupation was the beginning of an American Indian rights movement that had an international impact, which is ironical if you consider the purpose of this isolated and forbidding detention centre.

Perhaps it’s the unforgettable view from the island of San Francisco and the Golden Gate that keeps Alcatraz Tours so popular – everyone who takes a Tour has a different opinion of the merits of Alcatraz, but if you go there, keep an eye out for the ghosts of Al Capone and the Birdman of Alcatraz.