In January of 2015, after five hours of meticulous work with a small, dental tool-like metal pick and a porcupine quill, Museum of Fine Arts, Boston conservator Pam Hatchfield opened the oldest known time capsule in the country. It was originally buried on July 4, 1795 by Revolutionary War heroes Paul Revere and Samuel Adams, who was then the governor of Massachusetts. On that day, 15 horses—one for each of the states in the relatively new union—pulled the cornerstone for the new State House through the streets of Boston to the building site for a commemorative ground-breaking. Below the cornerstone, the two men placed the capsule, sandwiched between two sheets of lead.

And there it remained—but not without interruption. The capsule was first unearthed back in 1855, when workers discovered it while making repairs to the State House. It was opened at the time and the contents were cleaned (in nitric acid according to "preservation" tactics of the time), cataloged and re-buried along with artifacts from that era in a sturdy, brass box.

One hundred and fifty nine years later, the box is back out of the ground. In May 2014, historians—concerned about water damage from a nearby leak—decided it was time (again) to open the capsule. That December, Hatchfield spent seven hours carefully extracting the historic box.

Inside were five neatly folded newspapers, a collection of 23 coins dating as far back as 1652, a medal depicting George Washington, a replica of Colonial records, and a silver plate commemorating the erection of the new State House that reads, "This cornerstone of a building intended for the use of the legislative and executive branches of the government of the Commonwealth of Massachusetts was laid by his Excellency Samuel Adams, Esquire, governor of the said Commonwealth." Most of the items were already known from the 1855 catalog, but the details are still of tremendous historic value. Accessing this value presents some quandaries for the preservationists, though—like whether or not they should attempt to unfold the delicate newspapers to read what's inside.

Secretary of State William Galvin said the items will likely go on display for a short time and then they will go back into the time capsule and return to the original resting place in the cornerstone of the State House.