It's very hard for our puny human brains to understand the vastness of space and the immensity of time that has passed since the formation of the Earth or the universe. That's too bad, because some perspective on time and space could probably help make people realize the importance of long-term thinking and, thus, of protecting what we have for ourselves and future generations.
The website Here is Today attempts to provide some perspective on time by giving a visual idea of how much time has passed since various important milestones (biological, geological, centuries, millennia, etc). Just like staring at the stars in the night sky (or even better, at galaxies from a Hubble ultra-deep space image) makes us realize how small we are, staring at the vastness of time puts some of our small problems in perspective.
Via Here is Today
See also: If the Earth were 100 pixels wide...