An ocean liner is a big ship that people used to travel between continents before commercial airlines existed. They're a lot like modern cruise ships in a lot of ways, but they differ in a few key areas. They're similar in that they're designed to carry lots of passengers in accommodations that are as comfortable as possible. While they're similar in form, they differ greatly in function. Ocean liners are strong and fast. They had to keep to a strict schedule, like busses. Cruise ships never get all too far from land, and they can reschedule for bad weather. Ocean liners dont have those privileges. Liners are built to weather the Atlantic at its absolute worst. The most recent ocean liner to ever be constructed was the RMS Queen Mary 2 in 2004. Compared to a cruise ship of the same size, 60% more steel was used in her construction, because she needs to be strong and sturdy. Furthermore, people dont ride liners for leisure, like they would on a cruise ship. They have somewhere to be. So naturally, the fastest liner is going to get the most business. For over a century, companies competed with each other to build the fastest liners. Cruise ships can afford to kind of just meander from location to location. Ocean liners can't do that. They NEED to be fast. Does all of this make sense? Some examples of the most famous ocean liners of all time are the RMS Titanic and the RMS Queen Mary.