The virtual lab is kind of a "flight simulator" or quantum physics. There are programs that can guide students through concepts like delocalized complex molecules, with virtual experiments similar to what you'd do in a real lab. You can visit the lab for free online at http://interactive.quantumnano.at.
This virtual laboratory makes insights into fundamental concepts of quantum mechanics more accessible. For instance, very recently was the wave-particle dualism concept verified in a lab. Now students can run the same experiment, without the expensive equipment or institutional support.