Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. It’s been 250 years since the United States decided it was no longer interested in being part of Great Britain. To celebrate the momentous anniversary—called a semiquincentennial—the non-profit America250 has numerous events planned including something quite timely.  A roughly 2,000-pound time capsule will be buried at Philadelphia’s Independence National Historical Park on July 4, 2026. The capsule is intended to safeguard a snapshot of America today for another 250 years. While the process of burying random items underground for a few centuries might sound simple, designing and fabricating a storage container to withstand whatever nature might throw at it for the next 25 decades is quite the feat.  The team includes engineers from the National Institute of Standards and Technology (NIST) and preservation experts at the Library of Congress, who are coordinating with the National Park Service for the event in the nation’s first capital. NIST also designed and built the protective display cases that hold an original copy …