San Juan - Puerto Rico

This is an used Puerto Rico card i won in a lottery and it was sent from Norway by "BenteA".
Before postcrossing i thought Puerto Rico was a country but is a semi-autonomous territory of the United States.

This is "the Castillo de San Cristóbal is a Spanish fort in San Juan. It was built by the Spaniards to protect against land based attacks on the city of San Juan. It is part of San Juan National Historic Site (includes colonial-era forts, bastions, powder houses, and three fourths of the old city wall - classified as an Unesco World Heritage Site since 1983.)
Castillo de San Cristóbal is the largest fortification built by the Spanish in the New World. When it was finished in 1783 it covered about 27 acres of land, basically wrapping the city of San Juan. Entry to the city was sealed by San Cristóbal's double gates. After close to one hundred years of relative peace in the area, part of the fortification (about a third) was demolished in 1897 to help ease the flow of traffic in and out of the walled city." - in: wikipedia.