A flat-earth cruise sounds like a potentially dangerous venture if it gets close to the edge of the world.

But the Flat Earth International Conference (FEIC) is undaunted, promising a jaunt in 2020, the Guardian reported.

The navigation of the vessel could call into question their beliefs, however.

“Ships navigate based on the principle that the Earth is round,” Henk Keijer, a former cruiseship master who now works as a marine expert for Robson Forensic, told the newspaper.

“Nautical charts are designed with that in mind: that the Earth is round.”

Keijer also had a word of warning if FEIC wants to staff the ship with fellow flat-earthers.

“I have sailed two million miles, give or take,” Keijer said. “I have not encountered one sea captain who believes the Earth is flat.”