Water: Life on earth wouldn’t exist without it. 71 percent of the Earth is covered by water. That only leaves 29 percent for us humans to live – and not all of that land is inhabitable. Water is so important that most human settlements start near water of some sort. Water to drink, or water to move goods. With all this water in oceans, lakes, and rivers, it is no surprise that hackers, makers, and engineers alike build some incredible projects that work on and under the water.