Duque de Caxias Fort

This guide to Duque de Caxias Fort in Rio starts with an order the Brazilian Army placed with the German firm Krupp for eight giant howitzers to arm this lookout on Morro do Leme. It follows the awkward timing after Brazil joined the Allies against Germany in 1917, and the two rock-cut gun wells that were eventually built and sealed behind concrete casemates. You'll also hear how the site began a century and a half earlier as an unarmed watchtower, its only defense a pair of eyes scanning the bay.