Greece is a country made up of many islands, but only some of them are linked up by bridges. That leaves ferry boats as one of the primary modes of transportation between those islands, but the conditions on the Mediterranean, Ionian and Aegean seas aren't always hospitable. Just take it from these guys trying to load cars onto a Hellenic Seaways ferry.
Although the details are (quite literally) all Greek to us, as best we can tell, the vessel in question is the Apollon Hellas – a massive 300-foot ship capable of carrying 1,500 passengers and nearly 100 cars on board. Suffice it to say, then, that it would take some mighty stormy seas to rock the ship this much, but rock it does in this video clip.