"How I built a windmill" by William Kamkwamba

Power was scarce in William Kamkwamba's home country of Malawi, so he decided to collect his own energy.

The windmill Kamkwamba built is the subject of his 2007 talk, in which he describes the steps of collecting spare parts to build a multi-story structure that, once completed, could power four light bulbs and two radios.

The talk highlights just how far ingenuity can take someone if their drive is strong enough.