A Boston building site came to a dramatic standstill in May 2016 when construction workers uncovered an astonishing artifact. Indeed, the find was so rare and amazing that it set the city chattering with excitement.

Located within the city’s prestigious Seaport District is a thriving hub for high-rise condos, upscale eateries and towering office blocks. In fact, billions have dollars have been invested in the waterfront zone. However, the surprise discovery made here during new renovations was, in historical terms, priceless.

Skanska, the company hired to conduct the construction, is no stranger to big works. After all, it’s reportedly the world’s fifth largest construction company. Its commercial development projects, meanwhile, span the globe and include groundbreaking structures such as the World Trade Center Transportation Hub and the MetLife Stadium.