The crew of the Exploration Vessel Nautilus caught sight of a strange-looking formation while studying an area called Liliʻuokalani Ridge in the Papahānaumokuakea Marine National Monument in the Pacific Ocean.

The feature resembles a road paved in cobblestones. Impressed researchers viewing live dive footage of the formation described it as a “yellow brick road” and “the road to Atlantis,” and called it bizarre, cool and crazy in a video released last week.

Nautilus spent most of April studying geology and biological systems of seamounts, underwater mountains with volcanic origins. “At the summit of Nootka Seamount, the team spotted a ‘dried lake bed’ formation, now ID’ed as a fractured flow of hyaloclastite rock (a volcanic rock formed in high-energy eruptions where many rock fragments settle to the seabed),” the team said. The brick-like patterns likely come from heating and cooling cycles connected to eruptions.

The exploration vessel is operated by the nonprofit Ocean Exploration Trust, which live streams the ship’s adventures, giving viewers a firsthand look at what its remote-operated diving vehicles see in the deep. 

Nautilus has recorded all sorts of beautiful and unusual sea life, including cute dumbo octopuses and an oddball gelatinous creature from earlier this year.