Looking for a unique aged wine? You might want to start cave diving.

Marine archaeologists recently discovered a Spanish cave with about 200 submerged jugs of Roman-era wine.

The jugs, called amphorae, are ceramic containers with two handles that have been used to store grains or liquids like wine and olive oil since the Neolithic periods. But scientists say the recently found stash almost certainly dates to the Roman era, when international maritime trade was flourishing.

The cave, called Fuente de Ses Aiguades, is located off the coast of Mallorca in the Balearic Islands. It was first explored by archaeologists in 1998 and hadn’t been investigated since 2000. Previously, it was found that the cave, which is about 591 feet long, has a number of air pockets, stalactites, and vertical shafts that could only be reached using a pulley system.

During the recent cave exploration expedition, members of a group called Underwater Archaeological Research in the Caves of Mallorca were using new 3-D scanning technology to fully map the cave when they discovered the wine.

While scientists can’t say for sure why such a large number of amphorae would be collected in one place, they believe it could be part of an ancient ritual or ceremony.

Manel Fumás, a leader on the project, told Central European News that “ships used to anchor off the island to gather freshwater before going on their way.” It’s likely that sailors would try to win the favor of a god to ensure a safe voyage.

In the cave, there is a halocline, where layers of freshwater and saltwater meet but do not mix due to their differing densities. Because of this phenomenon, ancient people might have considered the cave a sacred place. And as the amphorae would have been very valuable during the Roman era, they would be considered a generous offering.

The amphorae are currently being studied by specialists who hope to find out more information on this mysterious discovery.