The highlighted region of this area of Planck data shows the position of a small patch of the sky that was observed with two ground-based experiments at the South Pole, BICEP2 and the Keck Array, and yielded a possible detection of curly B-modes in the polarization of the cosmic microwave background (CMB), the most ancient light in the history of the universe. However, a joint analysis of data from BICEP2, the Keck Array, and Planck has later shown that this signal is likely not cosmological in nature, but caused by dust in our galaxy.