Ada Lovelace, an English mathematician, is credited with writing the first algorithm intended to be processed by a machine. She worked with Charles Babbage's Analytical Engine and wrote an algorithm for it, making her the world's first computer programmer.

Alan Turing, a British mathematician, played a crucial role in developing the first electromechanical programmable computer, Colossus. Built during World War II, Colossus was used to break the German Enigma code, significantly aiding the Allied war effort.

John McCarthy, an American computer scientist, created LISP (LISt Processing), one of the earliest high-level programming languages. LISP introduced concepts such as symbolic computation and recursion, greatly influencing the development of artificial intelligence and modern programming languages.

Dennis Ritchie, an American computer scientist, created the C programming language while working at Bell Labs. C became widely popular due to its efficiency, flexibility, and portability. It laid the foundation for many other programming languages and operating systems, including Unix.

Tim Berners-Lee, a British computer scientist, invented the World Wide Web while working at CERN. He developed the first web browser and the first web server, along with HTML (Hypertext Markup Language), HTTP (Hypertext Transfer Protocol), and URLs (Uniform Resource Locators), revolutionizing information sharing and communication on the internet.