Puerto Rico is one of those little treasures that most people never hear about. It is one of those places that are not top of mind to visit but after you do, you will be coming time and time again for the rest of your life.
San Juan, Puerto Rico is rich with culture. The streets are filled with cobblestone as if from another era and the city is filled with history. I would start your adventure in Old San Juan wandering around the old cathedrals and making your way to the famous Castillo de San Cristobal. If you are feeling up to it perhaps a visit to Casa Bacardi (famous for rum) would be up your alley.
Another great day's adventure lies in the U.S's only national tropical rainforest, El Yunque. The rainforest is stunning and boasts awesome hiking adventures that you can take with a guide. Some of them even include snacks, water and a backpack. If the outdoors is up your alley, finish the day at some of the best beaches around. Luquillo Beach, Carolina Beach, and Ocean Park Beach are all great options for a short stay.
Off the coast of Puerto Rico is another island called Isla Verde. Known for its blue warm waters and tropical green looks, its a great place to go spend the day.
Overall San Juan Puerto Rico holds a bit of history, a bit of culture and always something tropical.