Borders are usually marked by fences, rivers, or mountains, but some natural borders are so strange that they defy logic. From zigzagging rivers to trees that split countries, these unusual frontiers prove that nature has its own way of dividing nations. Here are four of the strangest natural borders that separate countries.
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Diomede Islands – USA & Russia
In the Bering Strait, between Alaska and Russia, two small islands sit just 4 km (2.5 miles) apart, yet they belong to two different nations. Big Diomede belongs to Russia, while Little Diomede is part of the USA. What makes this border even stranger? The International Date Line runs between them, meaning the islands are in different time zones—Big Diomede is nearly a full day ahead of Little Diomede. This has earned them the nickname “Tomorrow Island” and “Yesterday Island.” Despite their proximity, crossing between them is illegal without special permits.
Everest Border – Nepal & China
Mount Everest, the tallest mountain in the world, serves as a natural border between Nepal and China (Tibet). The peak itself is divided between the two countries, meaning climbers can technically stand in both nations at the same time. Everest’s exact height has been a point of debate between the two countries, but in 2020, both agreed on the new official height of 8,848.86 meters (29,031.7 feet). The border adds an extra challenge for climbers, as different rules apply depending on which side of the mountain you ascend from.
Río de la Plata – Argentina & Uruguay
Unlike most rivers that serve as borders, the Río de la Plata between Argentina and Uruguay doesn’t have a fixed boundary. Instead, it’s a “movable” border that depends on the tides and water levels. Because the estuary gradually widens as it meets the Atlantic Ocean, its exact division remains unclear. Despite this, both countries peacefully share the river, using it for trade, tourism, and transportation. The region is also home to Montevideo and Buenos Aires, two of South America’s most vibrant capitals.
Baarle Border – Belgium & Netherlands
One of the most confusing borders in the world is found in the town of Baarle, which is split between Belgium and the Netherlands. Instead of a straight line, the border zigzags through houses, streets, and businesses, creating a strange patchwork of territories. Some buildings are literally cut in half, meaning a person’s bedroom could be in Belgium while their living room is in the Netherlands. The border is marked by white crosses on the ground, and shops follow different opening hours depending on which country their entrance is in.
These bizarre natural borders remind us that geography doesn’t always follow human logic. Whether it’s islands stuck in different time zones, a border that moves with the tides, or a mountain that divides nations, these unique frontiers make the world a fascinating place to look.
FAQs
Can you travel between the Diomede Islands?
No, travel between Big Diomede (Russia) and Little Diomede (USA) is restricted.
Which two countries share Mount Everest?
Nepal and China (Tibet) share Mount Everest as a natural border.
Why is the Baarle border so confusing?
It zigzags through buildings, dividing homes and businesses between Belgium and the Netherlands.
Does the Río de la Plata have a fixed border?
No, its boundary between Argentina and Uruguay shifts due to tides and water levels.
Why are the Diomede Islands called ‘Tomorrow’ and ‘Yesterday’ Islands?
The International Date Line between them causes a 21-hour time difference.
