A ~4200-foot (~1.3 km) asteroid named 2014 JO25 will fly by Earth on April 19, 2017. It will pass at a safe distance of ~1.1 million miles (1.8 million km). Delay-Doppler imagery of the asteroid from the Arecibo Observatory suggests that it's double the size that was previously thought.
This will be the closest fly-by of an asteroid this size or bigger since asteroid Toutatis in 2004 (Watch it tumble: )
Credit: Space.com / animations courtesy NASA/JPL-Caltech / edited by @SteveSpaleta