294 Dinosaurs Once Walked on This Wall in Bolivia

Millions of years ago, in the remote limestone landscape of central Bolivia, did dinosaurs have the ability to walk straight up vertical walls? That’s what it would seem from the strange footprints on Cal Orko, a nearly mile-long and 328-foot-tall slab of limestone imprinted with the weaving tracks of 294 distinct dinosaurs, representing at least eight species of the prehistoric beasts.

The 462 trails add up to 5,055 individual prints, the largest and most diverse collection of tracks in the world, and give the illusion that dinosaurs had the ability to walk directly up and diagonally across walls—this one sloping at a 70-degree angle. This is an astonishing proposition when you remember that some of these lumbering creatures weighed more than 100 tons.

As with all too-good-to-be-true mysteries, scientists have a simple explanation for this wall of wonder. The 68-million-year-old remnants of dinosaur feet were pushed upward by tectonic activity. The area, which once hosted a large lake, had an attractive climate that enticed herbivores and then carnivores. The dinosaurs walked across the area’s shoreline in damp weather, leaving their prints. During dry periods, the prints fermented, and when the rain returned, they were preserved under layers of sediment and mud. This process happened repeatedly, resulting in multiple layers of preserved evidence. Later, tectonic rumblings pushed the earth up into a massive vertical slab, and by virtue of its new position, protected it from modern devastation.

Set in what’s now a cement quarry, the phenomenon was unearthed not too long ago by miners who spotted the footprints in 1985. But researchers didn’t start to pay attention until a decade later when a Swiss paleontologist swooped in with a team to document the area. Through careful analysis, they found the simple footprints revealed telling signs of the dinosaurs’ build and lifestyle. In one finding, two lines of large prints with a small pair in between showed how parents raised their offspring.

In the years since, prints continue to crumble from the surface of the wall, while new ones emerge from underneath to take their place. The most famous trail of prints has been nicknamed “Johnny Walker” by researchers and was made by a baby Tyrannosaurus Rex. In 2003, the Bolivian government requested that the area be designated a UNESCO world heritage site, but it remains on the organization’s section of “Tentative Lists” awaiting approval.

Nearby, Cretaceous Park, a dinosaur museum that opened in 2006, features two-dozen looming replicas of the prehistoric animals and a viewing terrace from which visitors can appreciate the enormity of the area in which the former inhabitants once walked.