A 20,000 year-old coral reef, the only one in the Gulf of California, is at the center of a dispute over a huge tourist development which could draw thousands to a remote part of Mexico.
At the moment, most only hear about Cabo Pulmo, where pristine beaches meet a turquoise sea, by word of mouth.
US tourist Lenny McCarl said he discovered the village thanks to his girlfriend's family, during a visit in June.
"I like the little niche up here. You drive two hours outside of Cabo San Lucas and you're only 80 miles (130 kilometers) away, but there's no houses, there's just a villa here, a villa there," McCarl said, standing on the beach.
The site is less than two hours north of Cabo San Lucas and its luxury hotels and Hollywood celebrity-owned mansions, which have transformed the south of the peninsula in the past few decades.
The village also lies next to the site for one of Mexico's largest tourist development projects.
A wire fence marks out some 4,000 hectares (10,000 acres) destined to include several thousand hotel rooms and condominiums rising in five stages over 25 years.
The 500-million-dollar plan includes a tourist town "where school children will parade on the plaza," a jet port for private planes and golf courses.
Locals and environmental groups say the scale of the project is bound to impact on the land as well as the sea - with runoff from golf courses, desalinisation facilities and large yachts in a new marina.
"The government is blocking its ears and allowing a project like this, right on the limit of the marine reserve. As if there'll be no damage beyond an imaginary line," said Enrique Castro, whose family has lived in the area for five generations.
Commercial fishing is now banned and locals have spent 15 years changing their habits to try to preserve the reef under a government plan hailed as an example of conservation by ecologists.
Activities still revolve around the marine-rich Gulf of California, once nicknamed the "world's aquarium" by French explorer Jacques Cousteau.
Spanish company Hansa Urbana has meanwhile gathered permits to start building the Cabo Cortes development, including requirements for protecting the environment.
Such measures, including a ban on lights on the beach to avoid disturbing endangered turtles, water recycling and solar power, make the project 40 percent more expensive, representative Sergio Tabansky told AFP in Mexico City.
More than 60 percent of the land would be left for conservation, Tabansky said, admitting the eco-friendly label was also a good selling point.
"We want to help Mexico by giving jobs to Mexicans," Tabansky added, as the country struggles to emerge from one of its worst economic crises in years.
The H1N1 swine flu and the global crisis contributed to a drop of 1.1 million tourists in 2009 compared with the previous year, and a two-billion-dollar loss in revenues, the tourism ministry said recently.
Promotions and development plans are again picking up in a country which hosts some 22-23 million foreign tourists each year.
"Development is inevitable. What we can avoid are the (bad) terms under which we develop, right?" said Alejandro Gonzalez, who manages the Cabo Pulmo marine park for the government.
A handful of security guards patrol the vast site for Cabo Cortes on quad bikes for now, as the crisis has slowed construction.
Juan Castro, a former diver for pearls, and other locals hope the delay will buy them time to stop it completely.
"If the government allows this development, we can say that the government is the only one responsible for whatever damage is done to the reef," Castro said.
"It's the heritage of humanity. It's not mine, it's not yours."