The GRAND (Giant Radio Array for Neutrino Detection) is a proposed next-generation observatory of ultra-high-energy (UHE) neutrinos, cosmic rays, and gamma rays of cosmic origin, with energies exceeding 100 PeV. GRAND is a collection of large-scale ground arrays of self-triggered radio antennas that measure the radio emission from extensive air showers initiated by UHE particles. Three prototype arrays are in operation: GRAND@Nançay in France, GRAND@Auger in Argentina, and GRANDProto300 in China. While operating the prototypes and from the data they provide, the detection principle and technology of GRAND are tested, in preparation for its next phase. This will consist of two arrays of 10,000 antennas each, in the Northern and Southern hemispheres, to be deployed from 2028 on. We will present the concept of GRAND, its science goals, the status of the prototypes, their first measurements, and the technical and scientific perspectives that these measurements open for the field.