Mapimí Biosphere Reserve (Zone of Silence)

Mapimí Biosphere Reserve, known as the Zone of Silence, is a 103,000-hectare Chihuahuan Desert refuge that hosts the endemic bolson tortoise, one of North America's largest terrestrial tortoises at 40 kilograms, which outperforms #9 Pantanos de Centla's reptiles in size. Its ancient lakebeds harbor 20% of the world's cactus species, totaling over 300 types, which is twice the cactus diversity of the average Mexican desert reserve. The legendary 1970 US rocket crash that created radio signal failures adds cultural fame, but the reserve's conservation value is anchored in protecting 95% of the global bolson tortoise population.