Passengers on a cruise ship sailing through rough seas got more than they bargained for when waves up to 40 feet rocked passengers onboard.

Video posted to Instagram shows massive waves hitting the Quark Expeditions’ Ocean Explorer ship, which was traveling between Antartica and the tip of South Africa, known as the Drake Passage, according to the New York Post.

“Imagine if you signed up for a 48 hour rollercoaster,” one travel blogger wrote on Instagram. “Yes, we were safe and it was insane…and at times, even fun? 1000% worth it for this trip of a lifetime!”

Passengers on the cruise ship experienced rough waves while sailing through the Drake Passage. (@lesleyannemurphy via Storyful)

The company said its ships are “built to navigate such waters.”

Waves hit the window of the Quark Expeditions’ Ocean Explorer ship. (@lesleyannemurphy via Storyful)

“I am proud to say we survived not one but two Drake Shakes,” Murphy wrote. “If you’re lucky, you get the ‘Drake Lake.’ If you’re like us, you get the ‘Drake Shake’ with 35-foot waves.”