Things tend to pile up over 100 years when your mission is cataloguing and displaying the world’s natural wonders. Maybe that’s why only 2 percent of the items collected by the Smithsonian’s National Museum of Natural History are on public display.

But a new photo exhibit celebrating the museum’s centennial showcases more than 60 archival and modern photographs, allowing viewers an inside look at the most popular natural history museum in the world and its precious collections, past and present.

The museum, known for its Hope Diamond, massive blue whale and Tyrannosaurus rex facing off with a Triceratops, opened its doors March 17, 1910.

It has grown to encompass more than 126 million objects and specimens over seven departments: anthropology, botany, entomology, mineral sciences, invertebrate zoology, vertebrate zoology and paleobiology.

Some photos in the exhibit depict the domed building’s construction after the 1904 groundbreaking. Others show Smithsonian taxidermists preparing gigantic creatures for display: Four men work on a hippopotamus propped up on wooden supports in the 1930s in one image, and another shows a man inside the giant hanging blue whale’s mouth.

Visitors can also record their own memories about the museum at an interactive kiosk. Some of the videos will be featured on the museum’s YouTube channel.

But just like the museum has too many items to display, its history can’t be summed up in one modest exhibit.

To fill in the gaps, the museum created an online exhibit. In addition to an exhaustive timeline of the museum’s first 100 years, the site features the collections, stories about prominent people in the museum’s history and a blog where museum employees post videos. Entomologist Matt Buffington, for instance, explains to viewers how to photograph minute parasitic wasps.

The exhibit runs until March 2011.