See that white slope sliding into the top deck of that massive Caribbean cruise ship? That’s a ski slope, the first of its kind ever installed onboard a seagoing vessel.

The slope is 150 meters long and covered in a carpet of “Perma-Snow,” a substance some say feels just like real snow. We’re not so sure. For one, Perma-Snow will not melt under the hot Caribbean sun. Also, up close it looks like magnified velcro.

This week the slope gets its first run. The ship, a 1,129-passenger British behemoth called Iglucruise, embarked on an 8-day journey that will take tropical alpinists to Barbados, Tobago, and St Lucia, among other Caribbean ports. The cruise costs, at minimum, 799 British pounds or about $1,240.

Rock skiing, we hear, can be much, much cheaper.