The La Brea Tar Pits were first discovered in 1875 and researchers celebrated a milestone on Monday, marking a century of excavations at the site. The first 100 years have been full of discoveries and, with researchers continuing to find new fossils, the La Brea Tar Pits’ second century of excavations may prove to be just as fruitful.

The Associated Press’ report on the first century of excavations at the La Brea Tar detailed the many discoveries from the site, including bones from mammoths, saber-tooth cats, dire wolves and massive ground sloths as well as plant, reptile and bird fossils. The group of tar pits formed 50,000 years ago and the museum said the Los Angeles region was teeming with life, including American Mastodons, Camelops, an extinct species of camel that roamed North America, and giant jaguars. Animals would get trapped in the sticky asphalt and would die either from exhaustion or a predator, notes the museum.

The tar pits preserved much of this life during the Pleistocene epoch and while the majority of attention centers on larger discoveries, John Harris, chief curator at the George C. Page Museum, believes the plant, insect and bird fossils, excavated from the La Brea Tar Pits have provided the necessary information to make that understanding possible.

While the La Brea Tar Pits have been continuously excavated for 100 years, researchers are still dealing with a backlog of fossils and continue to make new discoveries on a daily basis. According to the AP, excavations of the tar pit have yielded more than 5.5 million bones, associated with 600 different species and there are thousands of fossils to catalog. Each day visitors can watch researchers clean and catalog fossils from the more than 100 pits that make up the La Brea Tar Pits.

The museum’s latest efforts, Project 23, began in 2006. Excavation for a new underground parking lot by the Los Angeles County Museum of Art led to the discovery of 23 new deposits as well as more than 300 buckets of fossil material. Researchers are working to clean and catalog the specimens and expect to double their fossil count by the time its project is complete. Other mysteries, such as how these species became extinct, remain, reports AP, which means the La Brea Tar Pits will continue to attract visitors and researchers for years to come.