Heading north from Esmeraldas, the vegetation and terrain turn quickly from forest and pastureland to an immense area of mangroves, rivers, and canals. The main town up here is San Lorenzo, an Afro-Ecuadorean city that feels a world apart from the rest of the country. San Lorenzo was once connected by railroad to Ibarra, but the train no longer runs all the way to San Lorenzo, and a road has been built to take its place.

There aren't many recommended places to stay in San Lorenzo. The surest bet in town is the Gran Hotel San Carlos, calles Imbabura and Juan José Flores (tel. 06/2780-284), which offers acceptable rooms -- some that even have air-conditioning and televisions.

One of the most unique places to visit in Ecuador is situated on a small island in the midst of mangrove forests outside San Lorenzo. La Tolita is an archaeological site, believed to be the remnants of one of the oldest pre-Columbian cultures in Ecuador. The people here smelted and worked with platinum, silver, and gold. It's not clear if La Tolita was a residential site or a purely ceremonial one. "Tola" is the word for a small, elevated mound or grave. When the area was first discovered, there were over 50 tolas on the island, many of which have since been plundered and destroyed. One of the most fascinating parts of a visit to La Tolita is Santiguero Beach, where, instead of sand or stones, the shore is littered with millions of shards of pre-Columbian pottery.

Most of the mangrove forests around San Lorenzo are protected as part of the Cayapas-Mataje Ecological Reserve. There are no real services or trails in this reserve; in fact it is principally accessible by boat. A boat ride through the rivers, canals, and lagoons here provides an excellent opportunity to spot hundreds of waterfowl, as well as caiman and other wildlife. The mangrove trees in this reserve are the tallest in the world, with some reaching nearly 60m (197 ft.).

You can hire a boat in San Lorenzo to take you to La Tolita or through the Cayapas-Mataje Reserve. You can ask around at the docks and usually find a boat and guide for around $12 (£8) per hour. But I think it's best to make day-trip arrangements through a hotel or tour agency in Esmeraldas or Atacames.

Warning: Although San Lorenzo is practically on the Colombian border, it is not recommended that you cross into Colombia here. Ongoing guerrilla activity and drug-trafficking activities make the area on the Colombian side rather dangerous for tourists.

By far, the best place to stay in this region is Kumanii Lodge (tel. 800/747-0567 in the U.S. and Canada; www.kumanii-lodge.com), located in the Chocó Rainforest. The lodge is run by members of the local Chachi indigenous and Afro-Ecuadorean tribes. Accommodations are a bit rustic, but the wildlife-viewing, cultural interaction, and sense of isolation definitely make it worthwhile. You can either fly directly into a small airstrip near the lodge, or take a 2 1/2-hour boat ride upriver from the coastal mangrove town of Borbón.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.