With a capacity of more than 16,000 TEU (twenty-foot equivalent unit shipping containers) the CMA CGM Marco Polo currently reigns as the "world's largest container ship" but it won't for much longer. Construction of an even larger line of mega-ships—the Maersk Triple E—will soon be complete and, once launched, will dwarf every other vessel on the high seas.

At 400 meters in length and capable of carrying 18,000 TEU containers, the new Triple E line will be the longest and highest capacity container ships in operation—larger than both the previous record holders, the Marco Polo and Emma Maersk. What's more, the Triple E's (which stands for "economy of scale, energy efficient and environmentally improved") will be far more fuel efficient than their predecessors. By chugging along at just 17.5 knots, rather than 20-25 knots as similarly sized ships do, the Triple E's will expend half as much fuel and 50 percent fewer emissions. The first iteration of the Triple E line is expected to float out of South Korea's Daewoo shipbuilding yard next June. [World's Largest Ship - Wikipedia]