An ion collider is a type of particle accelerator that collides ions at high speeds to study fundamental particles and forces. By smashing ions together, scientists can recreate conditions similar to those just after the Big Bang, allowing them to explore the properties of matter and the universe's origins. One of the most well-known ion colliders is the Large Hadron Collider (LHC), located at CERN in Switzerland. It accelerates heavy ions, such as lead, to nearly the speed of light, enabling researchers to investigate phenomena like quark-gluon plasma and the behavior of fundamental particles under extreme conditions.