When it comes to recognizing landmark tech and industrial pioneers, many people go straight to the usual suspects: Thomas Edison, Nikola Tesla, and Eli Whitney. Little do they know, sprinkled all throughout history are a number of black inventors and engineers that have made significant contributions to almost every faction of life through their creations. The cotton chopper, three-way traffic signal, and even 3D glasses—you’ll be shocked to discover what these famous engineers created. In celebration of Martin Luther King, Jr. Day, we take a look back at The 25 Most Important Black Tech Pioneers. Pay homage.