Seven centuries after the collapse of the Mayan civilization, a new kingdom—of high-end hospitality—is rising in Mexico's far east. Sarah Kerr reports

Beyond the jungle and the ruins and the powdery beaches, there is the eerie light that suffuses this part of the world in the off-hours. Wanting to see more, I trade in amenities one evening to watch the drama that plays out in the sky above Mexico's Sian Ka'an Biosphere Reserve. My humble hotel room will be a box-shaped tent mounted on a wooden platform and protected by a palapa roof whose damp scent of thatch sweetens the salt air. I lie swinging in a hammock near the tent, a football toss from the Caribbean Sea.

Later tonight, I'll walk uphill to the eco-lodge restaurant to eat a dinner of cilantro-slathered shrimp tacos and admire the eager yet dignified mutt, Sombra, who seems to be this place's mascot. But at this hour, in a 1.3-million-acre preserve whose name is said to mean Where the Sky Is Born, fading light is the main event. Looking east, I track a ghostly streak of orange-pink as it glides across the water. This is the sunset's reflection. To the west is the sun itself, red and sinking over a chain of lagoons. Soon the sky will darken. The minimal use of electricity around these parts shows off the galaxy, delineating the brightness and relative depth of the stars like a telescope. This glimpse of the universe is as moving as any I have had since one night, long ago, when I was camped high up in the Rocky Mountains.

A year has gone by since I first visited the strip of coast that runs north–south along the easternmost edge of the Yucatán Peninsula, in the state of Quintana Roo. A little over a decade has passed since the travel industry started to grasp the area's appeal—not just for the intrepid early adopters, who had been coming here for years, but for potentially huge numbers of new visitors. Despite lingering infrastructure challenges as well as setbacks like the two hurricanes of 2005 (October's Wilma was more famous, but July's Emily had her own vengeance to wreak), the move toward realizing that potential continues at an ever-speedier clip.

Development is occurring on multiple levels, from the eco-minded to the opulent to the all-inclusive. Because the attractions here tend to be more varied and more intense than those offered by the typical quick getaway, the area beckons splurging honeymooners, focused yoga devotees, American retirees in search of a second home. You can explore (gently, carefully) the great coral reef just offshore, or snorkel in a brisk cenote, one of the freshwater sinkholes formed on land when a cave collapses; you can bike around the jungle-sheltered remains of a classical Mayan city, or float down a mangrove canal dug a millennium ago by traders who needed to carry goods out to sea. Or you can do nothing but sit on a beach—a beach that outside the peak of high season remains reliably quiet, and which is not man-made but formed courtesy of fish that bite into the reef looking for algae and then pass through their system granules of soft calcium.