This fortress, with upper sections with a lighthouse and lower fort with bastions, was built by the Portuguese in 1612 to defend their assets in Goa, and also to store fresh water for their ships.
Both the upper and lower fort is made of laterite. Laterite rock rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content.
Although the dry, deteriorating stones look brown, those subject to erosion on the beach and those polished have a beautiful red color.