The Grand Canyon is one of the 7 natural wonders of the world. Here are 13 things you might not know about it.

Grand Canyon National Park/FlickrThe Grand Canyon is 277 miles long.
  • The Grand Canyon is one of the seven natural wonders of the world.
  • It’s 277 miles long and, on average, 10 miles wide.
  • Here are 13 things you probably didn’t know about the Grand Canyon.

The Grand Canyon is one of the most well known US national parks and one of the most visited attractions in the country. It holds a huge amount of history and information about the Earth, and at 277 miles long and, on average, 10 miles wide, it’s one of the seven natural wonders of the world.

Here are some surprising facts about the Grand Canyon.

Scientists aren’t sure how old it is.

Three Lions/Hulton Archive/Getty ImagesThe Grand Canyon in the 1950s.

Up until 2012, scientists thought the Grand Canyon – which has rocks as old as 1.84 billion years – was 5 million to 6 million years old. But in December 2012, researchers published a study that said the canyon could have begun forming as far back as 70 million years ago.

A 2014 study concluded that different parts of the canyon are different ages: Researchers said some parts of the canyon near its middle are 15 million to 25 million years old and another part is 50 million to 70 million years old. But the Grand Canyon as we know it today likely isn’t that old. Karl Karlstrom, one of the researchers, told Nature Geoscience, “Different segments of the canyon have different histories and different ages, but they didn’t get linked together to form the Grand Canyon with the Colorado River running through it until 5 to 6 million years ago.”

The weather is highly unpredictable.

The Grand Canyon’s shape and terrain affect air circulation and heat dispersion. The National Park Service says that average monthly high temperatures in the early summer are “more than 30 degrees warmer than average lows at all stations except Pearce Ferry,” that the canyon’s lowest elevations are its hottest, and that thunderstorms can appear quickly in the afternoon and lead to flash floods.

There are two rims, and one is more popular than the other.

The Grand Canyon has two main rims: the North Rim and South Rim. Most tourists visit the South Rim, which is open every day of the year and has most of the park’s lodging, museums, and visitor centres.

The North Rim is closed between December 1 and May 15, and according to the park service, only 10% of visitors to the park go there.

Read more: A 103-year-old woman just became a junior ranger for the Grand Canyon National Park, which didn’t actually exist when she was born

There are lots of fossils in the area.

Michael Quinn/National Park ServiceFossils found in the Grand Canyon’s rock layers.

According to park service, the Grand Canyon contains fossils from 1.2 billion years ago in Precambrian, which is the earliest geological time. Scorpions, crinoids, and dragonfly-wing impressions are common fossils in the area.

But if you’re looking for dinosaur fossils, you won’t find them at the Grand Canyon – the rocks are older than dinosaurs.

There are an estimated 1,000 caves in the Grand Canyon.

The park service says only 335 caves have been recorded in the Grand Canyon, though it’s estimated that there are up to 1,000. The service says most of the canyon’s caves are likely in the 505-million-year-oldMuav limestone layer and the 340-million-year-old Redwall limestone layer.

Fires are important for the canyon’s ecosystem.

Stuart Seeger/FlickrA dead tree in the Grand Canyon.

Controlled burns are necessary for forest health and safety. The park service says fires in the Grand Canyon help “wildlife habitat, nutrient recycling, plant diversity, and overall landscape health.”

Occasional small fires are a natural occurrence, and suppressing them – as has been done for the past century – leads to an unnatural accumulation of dead trees, needles, and brush on forest floors, which creates fuel for the larger wildfires that eventually break out and threatens new plant growth.

The canyon showcases a 1.2 billion-year gap in the rock record.

The Great Unconformity is the 1.2 billion-year gap in the rock record between the Cambrian period (485 million to 540 million years ago) and Precambrian, and the Grand Canyon is one of the best places to see it.

It’s not the deepest canyon in the world.

NASA/GSFC/METI/ERSDAC/JAROS, US/Japan ASTER Science TeamThe Yarlung Tsangpo Grand Canyon in Tibet is the deepest canyon in the world.

The Yarlung Tsangpo Grand Canyon in the Himalayas is the deepest canyon we know of. According to Live Science, it’s as deep as 17,567 feet. It’s also longer than the Grand Canyon, going on for 308 miles. The Grand Canyon reaches 7,800 feet deep, and is 277 miles long.

There are a number of Native American tribes living in the canyon.

Michael Quinn/National Park ServiceThe Colorado River in the Grand Canyon.

The Havasupai, Hualapai, and Hopi tribes, among others, have lived in and around the Grand Canyon for hundreds of years and now live on US government-designated reservations that are much smaller than their original lands. Many support their reservations through tourism. The influx of non-indigenous recreationists in recent decades has raised issues around respect to the land, which many Native Americans view as sacred.

Read more: It could take 300 years for Joshua Tree National Park to recover from the government shutdown

There’s only one town in the Grand Canyon.

The people of the Havasupai tribe live in Supai Village, which is the only town in the Grand Canyon and is an 8-mile hike from the canyon’s rim. All the village’s mail, including letters and food, is delivered by mule train.

Europeans first saw the Grand Canyon in 1540 but didn’t navigate it until 1857.

Spanish conquistador García López de Cárdenas is said to be the first European to see the Grand Canyon, in an expedition in 1540.

In 1857 and 1858 Lt. Joseph Ives took a steamboat partway up the Colorado River. He later wrote in his report that the canyon was “astounding” but “altogether valueless.”

In May 1869 geologist John Wesley Powell led a team into the Grand Canyon with four boats. His team navigated the Colorado River over the next three months, and one boat crashed in rapids. Powell went back in 1871 and mapped the river.

It’s had a number of different names.

The Hopi tribe calls the Grand Canyon Öngtupqa, which translates to Salt Canyon, and the Smithsonian reported that fur trappers based in Taos, New Mexico, knew of the Grand Canyon in the 1700s and called it the Big Cañon. Powell named it the Grand Canyon when he visited in 1869.

The Grand Canyon Museum has reportedly exposed tourists to uranium for 18 years.

In February, the Arizona Republic reported that the Grand Canyon Museum housed three buckets full of uranium ore between 2000 and 2018 in a building tourists were often in. The park’s safety, health and wellness manager, Elston “Swede” Stephenson, reportedly emailed park service employees on February 4 to say if they had been in the building in that time period they had been “‘exposed’ to uranium by OSHA’s definition.”

The son of a park service employee reportedly discovered the uranium in March 2018 with a Geiger counter.

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