It is an island off the coast of Brazil that is so dangerous, the navy sails around it to stop people getting ashore and soldiers and scientists are the only humans allowed to set foot on it. 

The island sits around 33km (20 miles) off the coast of Brazil and is known, ominously, as “Snake Island”. While its real name is Ilha da Queimada Grande, it’s not hard to see why it has been given its terrifying English name: it is home to thousands of venomous snakes, including a species of highly venomous pit viper found nowhere else on the planet. 

The deadly golden lancehead has fast-acting venom which cause a range of nightmarish symptoms. Up to 4,000 of them live on Snake Island, which has been ranked among the most dangerous islands on Earth. Its venom causes kidney failure, internal bleeding and the death of living tissue. It can kill in less than an hour. 

It’s possible that their venom evolved to be so deadly because no mammals live on the island so the snakes needed their venom to kill birds quickly, before they had the chance to fly away. 

The Brazilian Navy allows no one on the island other than scientific expeditions, though this is as much to protect the snakes as it is to protect tourists. Because the golden lancehead is so rare, its venom is prized on the black market, so they can be the victim of smugglers and poachers willing to risk their lives to get their hands on it. 

According to legend, one family did live on Snake Island in the 1900s to run the lighthouse but were killed by the snakes and no one has lived there since, with the navy patrolling to make sure no one gets ashore. One YouTuber managed to evade the navy to land there in 2023 and he wore body-armour to protect himself from snake bites.

Another legend which circulates about Snake Island is that the deadly vipers were taken there by pirates to protect treasure — through the reality is far more likely to be that the animals were simply left stranded when rising sea levels severed the island’s connection to mainland Brazil. 

The world’s deadliest islands

Here is a selection of other islands around the world that have been listed among the most dangerous on the planet. 

North Sentinel Island, India: Home to a secluded indigenous group of people thought to number between 50 and 100, reports say the inhabitants of the island do not welcome visitors and are happy to use violence to prove it.  

Miyake-jima, Japan: It has an active volcano, Mount Oyama, which has erupted several times in recent history.

Saba, Netherlands Antilles: The tiny island has been hit by more severe hurricanes in the last 150 years than any other.

Bikini Atoll, Marshall Islands: This is a Unesco World Heritage Site and is dangerous for two reasons: nuclear radiation and sharks. It was the site of more than 20 nuclear weapons tests between 1946 and 1958. The lack of fishing in the area means that sea life – including sharks – has flourished.

Farallon Islands, US: The sea around the Farallon Islands off the coast of San Francisco was used as a dumping site for radioactive waste for 30 years.