Spain’s King Felipe VI and Queen Letizia visit Castillo de San Marcos in St. Augustine, Florida on September 18, 2015. Castillo de San Marcos, a 17th century fort, was built by the Spanish when Florida (now part of the United States) belonged to Spain.
What is the name of the Hotel where they stayed ?
There’s an article about their trip to the US on the official Spanish monarchy website, http://www.casareal.es
If I’m reading it correctly, they may not have stayed in St Augustine at all, since they arrived there on the 18th and began their return to Spain on the same day.