The most popular natural tourist attraction in all of Jamaica, Dunn's River Falls is a many terraced fall that drops a total of about 180 meters (600 feet) through jungle ravines marred by the passage of a few hundred thousand tourists a year. Mostly done in tour groups, although you don't have to, this natural wonder near Ocho Rios is ripe for climbing and photo opportunities, although if you just want a great photo op in the midst of the untouched grandeur of nature, then you need to get there before the tourist buses or go somewhere else entirely.
Still, despite its tourist leanings, Dunns River Falls is also cool because it'll be different every time you visit. Thanks to the calcium carbonate in the water, it is a constantly reforming geological oddity. Tours can be booked from most hotel concierges, especially if you've put aside your scruples for a stay at one of the island resorts.