Before there were any solid physics theories, people already worked with the concept of energy. It was a life force, something that is all around us and inside us. But nobody less than Albert Einstein could have imagined that even a lifeless rock has a lot of energy, proportionate to its mass ($E=m{\mathrm{c²}}^{}$). This proved that even something as fundamental as energy can surprise us, which again highlights the beauty of physics.

Image by Burghard Mohren from Pixabay is licensed under CC0