Mayan Ruins in the Riviera Maya, Riviera Maya
Concierge.com's insider take:
For early Mayans who guided their ships through this coast's treacherous offshore reefs, the city of Tulum was a lighthouse: Firelight shining through window slits in the temples guided their way home. Today, the ruined city—the only settlement that the Maya ever built overlooking the sea—is still a must-see. As well as El Castillo, a tall ruined temple, Tulum has several small structures spread about a walled compound on cliffs above the water. Arrive early (it opens at 7 am) to beat the crowds, then climb down the hillside just south of El Castillo to the small beach with crystal-clear water. (There are no bathrooms, showers, or changing rooms here—so wear your suit and carry at least a liter of water.)
Cobá, about 30 miles northwest of Tulum, is surrounded by dense, often sweltering jungle—but its structures are much larger and many are beautifully preserved. You can climb Nohoch Mul, the tallest pyramid in the Yucatán region; its peak gives views over the treetops. You can also walk, bike, or hire a triciclo peddled by a modern-day descendent of the Maya to explore the paths that wind through the jungle and in between the site's ruined temples. You'll hear wild parrots swoop and squawk, and if you're lucky, you might even spot spider monkeys.