A major historical find was excavated in Stockholm, Sweden, earlier this year, when marine archaeologists dug deep beneath Kungsträdgården, a public park, and found bits of a 16th-century cargo ship that had been resting there for the past 400-odd years.

According to Smithsonian, the hiding-in-plain-sight discovery came as a result of construction workers breaking ground to help reinforce a building foundation near the park. That's when they found traces of the ship's hull. It’s possible the vessel, likely the Sampson and commissioned by Charles IX of Sweden in the 1590s, once docked on the coast while parts of Stockholm were still under water. The ship mysteriously disappeared from historical records in 1607. Apparently abandoned, it was exposed to the elements and stripped down for parts.

Because residents in Stockholm would often throw trash into the water, it’s possible the ship was eventually buried under the deluge and remained obscured even after the town drained the flooded areas of Stockholm's coast in the 1800s.

Marine archaeologists from the Swedish National Maritime and Transport Museums, among others, did the delicate digging, revealing building materials made of pine, and even naval guns. The Swedish National Maritime and Transport Museums did a 3D reconstruction of the find, viewable below.

[h/t Smithsonian]