The first few hundreds of millions of years (Myrs) of the universe include some of the most dramatic changes it has undergone, transforming from a near uniform distribution of gas into a diverse landscape of the first stars and galaxies. The early universe, characterized by an enormous abundance of pristine gas and by a dearth of massive structures looks quite unlike the universe today. If you were an observer peering into the young cosmos, you would be able to see very little around yourself, as the abundant neutral gas blocked most light from passing through and reaching you. However, the young stars in these early galaxies sent out high-energy photons throughout the expanse of gas, which ionized abundant hydrogen, eventually making the intergalactic medium transparent. The formation of the first galaxies, as well as their important role in reionizing the universe, is poorly understood because these galaxies appear faint owing to their distance, and are only visible in infrared wavelengths and beyond, altogether making them difficult to observe, especially from the ground.