Graphene is a single atomic layer of carbon atoms arranged in a flat hexagonal lattice. One atom thick. The thinnest material ever isolated. And yet, by almost every measurable physical property, it performs better than materials thousands of times its size.
It was first isolated in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester using adhesive tape and a pencil. The method was so simple it seemed absurd. The discovery was so significant they received the Nobel Prize in Physics in 2010.
What makes graphene remarkable is not any single property, but the combination: extreme strength, exceptional conductivity, transparency, and flexibility — all in a material that is effectively two-dimensional.