While sorting through old files at their summer job, three Boston University students discovered an exciting relic: a time capsule from 1915, which had sat forgotten in storage for 15 years, according to Boston.com.

As BU Today reports, undergrads Sarah Mankey, Emma Purtell, and Adam Mumford were tasked with sorting, recording, and re-packing hundreds of boxes filled with old university records while working for the college’s Facilities Management & Planning (FM&P) organization. The project took up much of the summer, but in early August, Mankey and Purtell—along with their work supervisor, Jeff Hoseth—came across a toaster-sized copper container, buried in a box along with university building records.

The time capsule had been buried in June 1915, the student workers later learned, when the cornerstone was laid for a Massachusetts Army National Guard Armory. In 2002, the building—called the Commonwealth Armory— was razed to build BU’s John Hancock Student Village complex. The armory’s original cornerstone was reset into one of the arena’s new walls, but the hidden box was stored away and presumably lost to memory with the passing years.

Mumford helped Mankey and Purtell unpack the time capsule, which had previously been pried open. It was filled with historic records, including a 1915 newspaper with articles about World War I and a map of the newly-constructed MTA subway to Harvard Square; old coins, including an 1894 quarter; construction records; antique photos; and rosters of men based in the armory.

BU officials said they were contacting the National Guard for guidance on what to do with the time capsule and its contents. In the meantime, the student workers who found the relic say it was a fitting reward for a summer of hard work.

[h/t Boston.com]