The Castillo de San Gabriel was built in 1573 in Arrecife on instructions of Agustín Herrera y Rojas and was meant as fortification against the many pirate attacks the island had to suffer back then. But already in 1586 the cruel attack by the pirate Morato Arraez proved that the four cannons, from which one was put on each side of the castle, were not enough to protect the capital from the assaults coming from the ocean side. In 1591 arrived Leonardo Torriani at the island who immediately started to plan on the improvements to be done on the castle. Finally, differing from Torrianis original plans, it was constructed a new way, protected by walls with escape exits and three cannons at each side. Still today this way connects the island which the castle was built on with the proximate shore line via a drawbridge of which type there can only found one in the whole Canary Islands.
In later refurbishment works the walls of the castle were strengthened and two more cannons were put on its roof.
Today the Castillo de San Gabriel is used as archaeological museum providing a great inside into the former life of the aborigines.
In the lower floor can be contemplated monoliths, anchors, stone paintings, fossils, clay and mud figures, ceramics, tools, statues, simbols and images of fertileness such as many skeletons, skulls and burial objects from the aborigines. In the upper floor can be found ceramics by Juan Brito an cannons.