10 places around the world that visitors cannot enter

Some of the world's most inaccessible places are not closed because they lack attractions, but because human visitors themselves could cause harm.

North Sentinel Island in India's Andaman and Nicobar Islands is home to the Sentinelese, one of the few remaining communities living in voluntary isolation. India follows an “eyes-on and hands-off” policy, designating the island and its surrounding coastal zone as a tribal reserve. Visitors cannot go ashore or approach it, with the restrictions intended to protect both the Sentinelese and outsiders from dangerous contact.

Iceland's Surtsey, a volcanic island that emerged between 1963 and 1967, is protected as a natural laboratory. Going ashore or diving near the island is prohibited, as are introducing organisms, minerals or soil and leaving waste. Only authorised scientific activity is permitted, allowing researchers to observe how life colonises newly formed land with minimal human interference.

France's Lascaux Cave shows how tourism can threaten ancient heritage. Its prehistoric paintings date back roughly 17,000 years, but the cave closed to the public in 1963 after visitor numbers and environmental changes contributed to biological problems that endangered the artwork. Visitors now see replicas and interpretation centres instead. The original Chauvet Cave, which contains some of the oldest known figurative cave paintings, never opened to mass tourism. Changes in humidity and air composition could damage the paintings, so access remains limited even for experts, researchers and conservators, while a replica offers the public an alternative.