In simple words its a machine that was built to understand creation of the world.
Some are afraid that it will open a black hole which will swallow the earth.


The Large Hadron Collider (LHC) is the world's largest
and highest-energy particle accelerator. It was built by the European
Organization for Nuclear Research (CERN) from 1998 to 2008, with the aim of
allowing physicists to test the predictions of different theories of particle
physics and high-energy physics, and particularly that of the existence of the
hypothesized Higgs boson and of the large family of new particles predicted
by supersymmetry. The LHC is expected to address some of the most
fundamental questions of physics, advancing the understanding of the deepest
laws of nature. It contains six detectors each designed for specific kinds of
exploration.

The LHC lies in a tunnel 27 kilometres (17 mi) in
circumference, as deep as 175 metres (574 ft) beneath the Franco-Swiss border
near Geneva, Switzerland. Its synchrotron is designed to collide opposing
particle beams of either protons, or lead nuclei.

It was built in collaboration with over 10,000 scientists and engineers from over 100 countries,
as well as hundreds of universities and laboratories