KAGRA is a 3-km laser-interferometric gravitational-wave detector under construction in Japan to form part of a network with other advanced detectors such as LIGO and Virgo. Innovative features include underground construction for lower seismic noise and cryogenic operation for lower thermal noise. Construction of the bKAGRA phase is essentially complete, and commissioning is underway, with the goal of participating in the LIGO/Virgo O3 observing run towards the end of 2019. The design and status of the detector are described.