Albert Einstein once dubbed quantum entanglement “spooky actions at a distance,” and the concept remains one of the starkest examples of how quantum theory differs from our usual intutions about space, time, and matter. Physicists have tested quantum entanglement in laboratories for more than forty years, and have always found results consistent with quantum theory; today entanglement is at the heart of next-generation devices like quantum computers and quantum encryption. Yet every experimental test to date has been subject to one or more “loopholes,” which could possibly account for the results even in the absence of genuine quantum entanglement. This talk describes the latest experimental tests of quantum entanglement, including a new experiment that uses some of the oldest light in the universe to address the last major loophole and pave the way for a genuinely loophole-free test of quantum entanglement.