One million tonnes of rock have been blasted from the top of a mountain in Chile, South America.
The explosion was done to make a flat spot to build the world's biggest ever telescope, called the European Extremely Large Telescope.
The telescope will have a mirror about half the size of a football pitch.
It will be made up of nearly 800 hexagon-shaped parts and will allow scientists to see deeper into space than ever before.
It's hoped astronomers will be able to see the first stars and galaxies that formed after the Big Bang, and also to find other Earth-like planets which might have forms of life.
The plan is for the Extremely Large Telescope to start working within the next 10 years.