Sian Ka'an Biosphere Reserve is just a few kilometers from Posada Dos Ceibas. The enormous reserve includes lagoons, mangroves, dunes, archaeological ruins, and exotic wildlife. For several hours, we poke around the reserve's beaches and scenic spots along the jungled stretch of road from Tulúm to Punta Allen. We top the hot afternoon off with icy margaritas and crunchy tacos at the Centro Ecológico Sian Ka'an, where, if you are so inclined, you can book half- or full-day tours.

On our one cloudy day, we visit the Mayan ruins at Tulúm. The walled site sits on a bluff above the sea, and the stone buildings date from the 1500s and earlier. Our hotel's staff advises us to go early, before the tourist buses arrive—this is enough to get BJ to commit to an 8 a.m. excursion. We make our way along the low stone wall and through a narrow entrance into the guarded portion of the ancient city. Signs tell the story of what once was a fort and sacred site along an important trade route. We wander, and admire, and take far too many pictures.

BJ and Dana with Norma, the Spanish instructor, at Posada Dos Ceibas in Tulúm (Courtesy Dana Lucero) [enlarge photo] EVER DREAM OF BEING A TRAVEL WRITER? • A Family Trip to Hong Kong • A Treehouse Adventure • The No-Frills African Safari • I Married a Non-Traveler • On Tour in the Emerald Isle MORE ON MEXICO • Destinations: Mexico • Nonstop Mexico • Slide Show: Mexico, Old and New • I Married a Non-Traveler: A Writer Convinces Her Husband to Try Cancún • 2007 Scouting Report: Puerto Ángel • Got Stress? Get to Puerto Vallarta • Secret Hotels of the Riviera Maya • Romancing the Bean • 25 Reasons We Love Oaxaca • Ghosts of the Sierra Madre

The last item on my must-do list is a trip to one of the cenotes—deep natural wells or freshwater cave systems found throughout the Yucatán. If you're like us and prefer to go it alone, many of them are easily accessible from major roads. We visit Gran Cenote and snorkel amid colossal stalagmites, stalactites, and tiny fish. We watch with envy as scuba divers sink deeper into the dark and mysterious cave. We kick ourselves for not buying an underwater camera. The still, fresh water is a nice change from the Caribbean, if such a thing is possible.

Meet halfway
As our time in Mexico comes to a close, we're both very aware that by not traveling more often all these years, we've been missing out. We both know we'll be back—if not to this spot, most certainly to this state of being.

Personally, the biggest lesson that I learn is that while it was easy to think that BJ was the reason we failed to travel, I need to own up to my role. I thought relaxation-themed travel was only for the lazy or unimaginative, and I was certain that I'd be dissatisfied lying around on a beach or lolling in a hammock. But I surrender. On this trip I relished doing nothing almost as much as I loved exploring the Yucatán. Ultimately, we highly recommend both!

Lodging

Ambiance Villas
Blvd. Kukulkan, Km 8.5, Zona Hotelera, Cancún, 011-52/998-891-5400, ambiancevillas.com, from $110

Posada Dos Ceibas
Km 10, Carretera Tulúm-Boca Paila, Tulúm, 011-52/984-877-6024, dosceibas.com, from $60

Activities

The Pink Iguana Language School
011-52/984-124-0034, thepinkiguana.com, five-day course $260

Centro Ecológico Sian Ka'an
Carretera Federal 307, Tulúm, 011-52/984-871-2499, cesiak.org, tours from $50