Visiting Puerto Rico a few years ago we explored the Castillo San Felipe del Morro, set at the entrance to the Bay of San Juan.  It was an important defense built by Spain with construction starting almost 900 years ago!

I captured this photo looking down the barrel of one of the canon that allowed the Spanish to thwart attempts by the British, Dutch and numerous Pirates from entering the Bay – one of the most strategic harbors in the Caribbean for large ships.  

This photo allows you to really “feel” the texture of the rusted canon and the slowly decaying edifice of the fort, while also enjoying the blue of the ocean and the sky.