A well-known geological formation in Utah known as the “Double Arch,” which towers over Lake Powell in the Glen Canyon National Recreation Area and is made of 190 million-year-old Navajo sandstone, has collapsed.

No injuries were reported in Thursday’s incident, the National Park Service said.

“Since its formation, this fine-grained sand formation has been subject to spalling and erosion by weather, wind and rain,” officials said Friday. “Changes in water level and erosion from wave action are likely to have contributed to the arch’s ultimate collapse.”

The tourist attraction, also known as the “toilet bowl” or the “hole in the roof,” had attracted countless visitors to Glen Canyon. Although the attraction itself is now lost, a park ranger is urging people to look to the future.

Michelle Kerns said in a statement: “This event reminds us of our responsibility and need to protect the mineral resources surrounding Lake Powell. These features have a lifespan that can be impacted or damaged by human intervention.”

“While we don’t know what caused this collapse, we will continue our efforts to protect Lake Powell’s resources so future generations can continue to benefit. Please enjoy our resources, but leave no trace.”

Before the collapse, chunks of rock fell from the Double Arch into the water below; the resulting splash was captured on video.

“I looked over and a couple of the guys I was with had seen a big piece of rock fall from the bottom of the arch into the lake,” boater Merril Campbell told KSL-TV, adding, “It was like a boulder the size of a Volkswagen.”

Locals and tourists expressed their condolences on social media.