In the early 1920s the land that is now Cariló was nothing but coastal dunes with barely any vegetation, part of a 1,700-hectare estate of shifting sand used for cattle ranching. Héctor Manuel Guerrero set out to change that, launching an ambitious afforestation project on his property, which he called Dos Montes. It was not easy. There were no roads in, no infrastructure, and almost no local knowledge about how to anchor a moving dune. Guerrero and his team experimented their way forward, testing tree species and planting methods, working in pines and fruit trees to fix the sand and lure native birds. By 1935 the new green expanse had a name: Cariló. By 1947, more than 660,000 trees had been raised for planting.

When Guerrero's descendants laid out the town, they did something quietly poetic. The streets are named not for politicians or saints but for the living things around them, and they are organized with an almost botanical logic. Roads running perpendicular to the shore are named after native plants and trees; roads running parallel to the coast are named after local birds. Both sets march in alphabetical order. To walk Cariló is to read a field guide written into the map itself. The estate's grand main house, Divisadero, also called Casa Grande, was built on a dune facing the Atlantic in 1948, and by the 1970s the family had finished transforming the whole property into a mature coastal forest. The tree nurseries, no longer needed, were shut down.

The rules that made Cariló keep it intact. Local ordinances still protect the forest, limiting how many trees may be removed and requiring replanting for any that come down. There is no race to pave the trails or clear the lots; the sandy roads and the pines are the entire point. Buildings are individually designed and slotted between existing trees, so that even the hotels and shops seem to grow out of the woods rather than displace them. It gives the place a hushed, filtered quality, light falling green through the canopy onto sand. For most of the year Cariló is nearly empty, with only a handful of permanent residents, before the summer floods it with visitors.

Step out of the forest and the Atlantic opens up in wide, sandy beaches, most of them free and open to anyone. A few stretches are run by beach clubs with literary names like Hemingway and Neruda, and in places you can drive a four-by-four right onto the sand. Between the trees and the waves there is plenty to do: surf schools line the beach, horseback riders and hikers thread the wooded dunes, and the Cariló Golf Club lays its sloped fairways and blind shots among the pines. Families climb the zip lines and rope bridges of the Bosque Aéreo, an aerial forest park. It is a strange and lovely thing, this town, half woodland and half shore, every bit of it planted on purpose where the wind once moved only sand.