Nikola Tesla was an electrical engineer who made significant contributions to the development of electricity and wireless technology. He is best known for his work on alternating current (AC) electricity supply systems, which revolutionized the way electricity was used in homes and businesses. He also developed the Tesla coil, a device that produces high-voltage, low-current electricity. Tesla's inventions and discoveries have had a lasting impact on the world and he is widely regarded as one of the most influential scientists of all time.