Archaeologists in Japan have unearthed a massive stash of about 100,000 coins in Maebashi, a city about 60 miles (100 kilometers) northwest of Tokyo.

The hoard was found during excavations ahead of the construction of a factory, reported The Asahi Shimbun, a newspaper in Japan. Only 334 of the coins have been examined so far, with the oldest one originating from China and dating to 175 B.C. and the most recent coin dating to A.D. 1265, the newspaper reported.