For most of history, the North Pole was the stuff of legends and wild theories. But even after European explorers got close to it in the late 19th and early 20th centuries, the North Pole remained mysterious. Here are 11 facts we know about the North Pole so far.

1. The North Pole has no time zone.

Besides visiting explorers, tourists, and researchers, humans do not live at the North Pole. And because there are no permanent settlements, the North Pole has not been assigned a time zone. People at the North Pole can choose to go by any time zone that is convenient. The closest permanently inhabited place is Alert, a military installation 600 miles to the south on Ellesmere Island in Nunavut, Canada, and it’s in the Eastern Time Zone.

2. There is no land at the North Pole.

The North Pole has no land mass at all. Instead, it’s made up of huge ice floes, 6 to 10 feet thick, that float on the surface of the Arctic Ocean. Beneath the ice, the water is 13,400 feet deep.

3. At the North Pole, the sun rises and sets just once a year.

At the North Pole, there is only either light or darkness. The sun rises around the spring equinox on March 20 and stays in the sky for a full six months before finally setting around the fall equinox on September 22. Through the winter, the North Pole is dark 24 hours a day until the sun finally begins to reappear in March.

4. Two competing explorers claimed to be first at the North Pole.

In the early 20th century, the North Pole was one of the last places on Earth yet to be “discovered.” That changed in 1909 when, in the same September week, newspapers reported that not one but two explorers had made it to the top of the world. The famous American explorer Robert E. Peary claimed to have reached his destination in April 1909, his eighth attempt. But another American explorer, Frederick E. Cook, came out of nowhere to claim he was first in April 1908, a full year before Peary.

Despite the competing reports, Peary was widely acknowledged as the first at the North Pole until 1988 when, after re-examining his records, the National Geographic Society concluded that he might not have made it to the North Pole after all. Even if he did, it’s likely that his teammates, Matthew Henson and four Inughuit guides Ootah, Seeglo, Egingwah, and Ooqueah, were actually the first to set foot at the pole—because Peary had to ride on a sled due to the loss of eight toes to frostbite.

5. The Soviets established the first research camp at the North Pole.

Unlike in Antarctica, where permanent research stations were established as early as the 1940s, there is no equivalent at the North Pole. The Soviet Union established the first temporary research station there in 1937. Planes dropped four men, including an oceanographer, a meteorologist, and a radio operator, on a 10-foot-thick ice floe in March, and over the next year they studied the Arctic environment. When the expedition concluded in February 1938, rescuers found the station not where they left it, but drifting in the Greenland Sea, 1615 miles away. After several failed rescue attempts, all four researchers were safely evacuated and returned home.

6. Santa Claus moved to the North Pole in the mid-19th century.

Santa Claus, the North Pole’s most famous resident, didn’t always live within the Arctic Circle. Saint Nicholas, the 4th-century religious figure from whom the myth of Santa Claus is derived, came from Myra, a Roman town in what is now Turkey. But in the mid-1800s, cartoonist Thomas Nast began depicting the saintly character as we know him today: fat, jolly, and with a sack full of toys. Because a flurry of American and European expeditions to the Arctic captured the world’s imagination around the same period, Nast selected the fabled location for Santa’s permanent home.

7. Russia staked its claim to the North Pole with an underwater flag.

In 2007, two Russian submarines embarked on a record-breaking dive to the seabed of the North Pole, two-and-a-half miles beneath the surface of the Arctic Ocean. But it was oil and gas, not the thrill of exploration, that drove their expedition. On the ocean floor, the submarines planted a 3-foot Russian flag made of corrosion-resistant titanium, staking its claim to what is believed to be almost a quarter of the Earth’s oil and gas reserves underneath. Russia argued that the North Pole is merely an extension of the Lomonosov Ridge, an underwater chain of hills extending from the Russian mainland, and therefore Russian territory. Denmark argued that the ridge is actually an extension of Greenland, and thus Danish territory. While Russia congratulated itself for the move, the rest of the world was not amused. More than a decade on, Russia’s claim to the North Pole’s resources has not been recognized by the United Nations.

8. There aren’t many plants and animals at the North Pole compared to the rest of the Arctic.

Despite the frigid and fluctuating climate, the Arctic is incredibly biodiverse. More than 21,000 species of plants and animals are adapted to the extreme landscapes. But at the North Pole, where there is no land or terrestrial flora and fauna, wildlife is fewer and farther between. Arctic cod, shrimp, and crustaceans live at various depths under the sea ice, while the most common sights above the ice are migrating birds, such as Arctic terns, fulmars, kittiwakes, and snow buntings.

9. A Japanese adventurer rode a motorcycle to the North Pole.

In 1987, Tokyo motorcycle shop owner and racer Shinji Kazama left Canada’s Ward Hunt Island bound for the North Pole on his Yamaha TW200. Kazama and the five members of his support team traveled 1250 miles over sea ice in conditions so extreme that, at times, the motorcycle could only travel 30 feet per hour. It took the adventurer 44 days to reach his destination. Five years later, in 1992, Kazama completed the same feat at the South Pole, becoming the first and only person to have ever reached both poles by motorcycle.

10. The North Pole hosts an annual marathon.

Since 2003, the North Pole has hosted an April marathon for the world’s most extreme athletes. The 26.2-mile race is run on a hard snow and ice track with competitors braving frigid temperatures that, in past years, have dropped as low as -20°F (-29°C). The current record for the fastest time at the FWD North Pole Marathon is held by Irishman Thomas Maguire, who ran the race in three hours and 36 minutes in 2007.

11. The North Pole could be ice-free in summer in less than 30 years.

The Arctic is warming at twice the rate of the rest of the globe. As the climate crisis deepens, scientists expect that within fewer than three decades, sea ice cover will completely disappear in the summer months unless global emissions can be significantly reduced—and quickly. And because what happens at the North Pole impacts the entire Earth, the seasonal disappearance of ice will likely lead to rising sea levels, more severe weather events, and drastic changes in climate and precipitation on all seven continents.