The History Channel dedicated an episode of its series "Modern Marvels" to Tesla, whose bizarre vision of the future brought him failure, but his genius electrified the world. Travel to Niagara Falls, where in 1893, Tesla installed his new system of Alternating Electrical Current known as A.C. -- the same power we use today. Uncover the forgotten ruins of Tesla's dream experiment -- a huge tower on Long Island Sound he hoped would wirelessly power the world. Radar, death rays, invisibility devices and earthquake machines: Tesla envisioned them all. More than 100 years ago, Tesla foresaw the need for alternative energies like geothermal and solar.