Some of the largest ships in the world come in the form of oil tankers, cargo carriers, and cruise liners. These mega machines are marvels of engineering and contribute to a huge percent of the world's transported goods, not to mention people.

And who says that size doesn't matter?

The sheer sight of one of these supertankers up close makes one realize the true gravity of the manufacturing and design techniques involved in the construction process. These monumental machines require massive propulsion systems. Some diesel, some nuclear, some wind, and some even solar-powered.