Grace Murray Hopper: A mathematics PhD who joined the Navy during WWII, Grace Hopper worked on the Harvard Mark I and became one of the first programmers of the digital age. Her true genius was making computers accessible. She pioneered the first compiler and helped establish COBOL, using English-like commands instead of machine code. By the 1970s, COBOL was the most extensively used computer language in the world.

Hopper retired as a Rear Admiral at 79 and was affectionately known as “Grandma COBOL.”

Fun Fact #1: Grace coined the term a “computer bug.” Once when her team was working on a computer glitch, she discovered the problem was an actual bug—a live moth stuck in an electrical switch.

Fun Fact #2: Grace notoriously kept a clock her wall that ran counter-clockwise to remind herself to be open to new ideas. “Humans are allergic to change,” she said. “They love to say, ‘We’ve always done it this way.’ I try to fight that. That’s why I have a clock on my wall that runs counter-clockwise.”