The Smithsonian’s National Museum of Natural History opened its doors 100 years ago today, on March 17, 1910. To mark the occasion, the museum has opened a brand new exhibit hall, the David H. Koch Hall of Human Origins, a large permanent exhibit dedicated to the discovery and understanding of human origins.

And as a great afternoon time waster, check out this slideshow depicting the museum’s transformation over the past 100 years. The original budget for building the NMNH was $3.5 million, a paltry sum in today’s dollars. Some 290 million people have visited the museum since it first opened.