Although it may be fun, Texas State Parks and Wildlife officials are gently reminding visitors not to stack rocks at any of their parks, reports KVUE.

Stacking rocks is not only illegal, but it can be very dangerous to hikers and contribute to damage to the state park’s natural ecosystem.

The golden rule of camping, hiking, and other outdoor activities at state parks is to leave no trace of evidence that anyone was even there. Rock stacks –otherwise known as rock cairns–have the ability to cause damage to the environment and ecosystems surrounding them.

“Doing so disturbs sensitive and critical wildlife habitats that rely on the rocks for protection. This is even more serious during times of drought and low water levels just like we are experiencing here at the park,” Dinosaur Valley State Park said in a Facebook post. “Wildlife are already isolated to specific areas of the river and streams when water levels drop, and the building of rock cairns destroys what habitats are left. This results in those wildlife species moving somewhere else causing a break in the ecosystem.”

The animals that make up the Texas state parks rely on existing rock formations to protect themselves against predators and weather conditions.

“Aquatic macroinvertebrates help indicate overall water quality, and are crucial to the freshwater ecosystems for other species such as fish,” the Facebook post continues. “While their job and role in the environment becomes (sic) much harder during times of low water and drought, it becomes near impossible when rocks are removed to build rock cairns.”

When people stack rocks at state parks, it can also confuse hikers and bikers using trails, causing them to become lost.

Rock Cairns are common throughout human history, dating as far as prehistoric times, according to advnture.com.