One of the world’s most famous landmarks is reportedly not as old as researchers initially thought. The Grand Canyon took its form relatively recently, according to researchers at the University New Mexico at Albuquerque.

“The ‘old canyon model’ has argued that the Grand Canyon was carved 70 million years ago in the same place and to nearly the same depth as the modern canyon. We are refuting that,” Prof Karl Karlstrom from the UNM-Albuquerque, told BBC News.

“We are also refuting the ‘young canyon model,’ which claims the canyon was cut entirely in the last six million years. Instead, we show that the Colorado River used some old segments as it found its path from the Rockies to the Gulf of California in the past six million years,” Karlstrom added.

The researchers examined the time of formation of four out of five segments of the Grand Canyon, utilizing apatite fission-track dating, track-length measurements and apatite helium dating. They discovered that two of the three middle segments, the Hurricane segment and the Eastern Grand Canyon, developed between 70 and 50 million years ago and between 25 and 15 million years ago, respectively. However, they discovered that the two end segments, the Marble Canyon and the Westernmost Grand Canyon, are both young and were carved in the past 5-6 million years.

According to The Washington Post, even though the new study comes with some compelling evidence, researchers behind the old canyon model are skeptical. University of Colorado geologist Rebecca Flowers, for example, told The Washington Post via email that “it will take a bit more time to understand fully why their interpretations are so different from ours.”

According to the National Park Service, the Grand Canyon is 277 river miles long, up to 18 miles wide and a mile deep. In addition, five million people travel to see the one-mile deep Grand Canyon each year.

The study’s findings are published in the journal Nature Geoscience.