Astronomy is about exploring the universe, discovering what’s out there, and using science to understand it. Our exploration is carried out with telescopes, so as telescope technology evolves, so does our understanding of the universe. Over the last hundred years, telescopes have become bigger, better and more diverse. This rapid evolution has led to a far wider and deeper picture of the cosmos we inhabit. In this talk, I will highlight key advances in telescope technology over the last century and illustrate the major discoveries that have resulted from them. I will also look forward to the science that might be done with the new generation of telescopes currently under construction.