Graphene has the highest ever tested tensile strength of 130 gigaPascal. For comparison that's about 125 times stronger and six times lighter than steel, while still being flexible and elastic, retaining its initial size after being stretched.
In addition, it conducts heat and electricity 10 times better than copper, with very low resistance.
Its ability to absorb 2.3% of white light is much, considering it is 1 atom thick. Adding more layers increases the opacity by the same value (2.3%) per each layer.
Graphene also is very dense, making it impermeable even for gases with small atoms like helium.
Furthermore, it’s properties can be altered when adding chemicals to its surface.
Graphene was first produced by André Geim, Konstantin Novoselov and their Team of the University of Manchester in 2004. They created it by using tape to pull off thinner layers of graphite until only one layer was left. For this discovery, both Physicists won the Physics Nobel prize in 2010.