Filadelfia is the main town of the Fernheim Mennonite colony in the Gran Chaco, 480km northwest of Asunción along the Trans-Chaco Highway. It's a tidy, well-organised settlement of around 15,000 people — a striking contrast to the surrounding wilderness. The descendants of Low German-speaking Mennonites who fled Russia and Canada in the 1920s run a successful agricultural co-operative here, primarily dairy farming and cattle.
The town's two small museums, the Colony House Museum and the Jakob Unger natural-history museum, document the colonisation of the Chaco and the local flora and fauna; both are genuinely interesting. A few basic hotels and restaurants cater to travellers along Avenida Hindenburg, and the local dairy products — cheese, yogurt, butter — are excellent and worth stocking up on for the road.
Filadelfia is the main base for wildlife-watching excursions into the Chaco. Local guides offer 4WD trips to water holes and wilderness areas where jaguars, giant anteaters, tapirs, and extraordinary birdlife can be seen, particularly in the dry season (May–September). Without a guide and 4WD, venturing deeper into the Chaco is not advisable.