San Juan, Puerto Rico
Great for: Wilderness hiking, historic sites, dining, nightlife
If you’ve only got six hours: Take a short tour bus ride to El Yunque, the only tropical rainforest in the US National Park System. You won’t have time to hike to the top of the Caribbean’s tallest mountain, but it’ll expose you to some wilderness you don’t get back home.
Since it’s a major port of departure for cruises to the Southern Caribbean, San Juan is hardly a hidden gem. But with Old San Juan just a short ride away — where you can hit up the 16th-century El Morro and 18th-century Fort San Cristobal — it’s your best chance to explore Spanish colonial history on a cruise.
Puerto Rico is huge, and the best beaches aren’t necessarily doable in a day. But the rainforest at El Yunque can be visited in a few hours, the Bacardi distillery isn’t far out of town, and the dining options are expansive.