When it comes to waves, it doesn't get much bigger than the gravitational variety. Einstein predicted that huge events — like black holes merging — create gravitational waves. Unlike most waves we experience, these are distortions in space and time. They roll across the entire universe virtually unimpeded.
Einstein first predicted the existence of gravitational waves in 1916, but none were spotted until recently. Given their incredible power, why did it take a century to locate them?