Since the earliest times, we humans have attempted to understand and explain the world around us by observing our surroundings. By building tools such as telescopes and microscopes, we have been able to see phenomena ranging from the cosmological scale to the nanoscale, and, on the way, we have learned a huge amount about how our world works. As we scientists seek to measure ever fainter signals to uncover the workings of our universe, we have learned to take advantage of the mysterious quantum world to unlock ever more sensitive "eyes." In quantum mechanics, nothing seems to work the way we might expect – a weirdness that we can leverage to build the world's most sensitive detectors. In this lecture, I will discuss how some of these amazing sensors work, and I will describe some of my work building new quantum tools to measure the universe as well as some of SLAC's other efforts as a leader in this nascent field of quantum sensing.