When was the transmission electron microscope invented?

The transmission electron microscope (TEM) was invented in the 1930s, with significant advancements made by physicists Ernst Ruska and Max Knoll. They developed the first functional TEM in 1931, which allowed for the visualization of ultra-thin samples at much higher resolutions than light microscopes. This groundbreaking invention has since revolutionized materials science, Biology, and Nanotechnology.