The island is inhabited by a vast number of venomous snakes, making it off-limits to all but the nation’s navy and select researchers who undergo thorough screening.

Located off Brazil’s coast, a small yet highly dangerous island remains inaccessible for an unusual reason. Ilha da Queimada Grande, situated in the Atlantic Ocean, spans only 43 hectares (106 acres).

The island has earned its infamous reputation due to the dense snake population—roughly one per square meter—leading to its chilling nickname, “Snake Island.” It is the exclusive habitat of a rare viper species found nowhere else on Earth. To protect both this endangered snake and to shield humans from its deadly venom, access to the island is strictly banned for tourists, with only a select few authorized visitors permitted to approach.

Snake Island experiences a temperate climate, with its landscape ranging from exposed rock formations to lush rainforest areas.

The island is the sole natural habitat of the critically endangered golden lancehead pit viper (Bothrops insularis), a venomous species. These snakes were isolated on the island thousands of years ago when rising sea levels at the close of the last ice age separated the island from the mainland.

The species’ adaptation to its isolated environment, coupled with a significant increase in its population, made the island far too hazardous for public access.

Currently, Snake Island is off-limits to the public in order to safeguard both humans and the snakes, with access granted solely to the Brazilian Navy and approved researchers who are screened by the Chico Mendes Institute for Biodiversity Conservation, a federal conservation body.

Earlier estimates suggested that the snake population numbered around 430,000, but more recent assessments indicate a significantly lower count. The first comprehensive study of the golden lancehead population revealed that there are between 2,000 and 4,000 individuals, mostly confined to the island’s dense rainforest region.