Completed in 2021, the Large High Altitude Air Shower Observatory (LHAASO) is the most sensitive instrument probing the sky in the ultra-high-energy (>0.1 PeV) gamma-ray domain. It already detected about a dozen sources whose spectra extend to PeV energies. Such energetic photons are produced in interactions of multi-PeV cosmic rays with ambient matter. LHAASO sources have been tentatively associated with pulsar wind nebulae, young massive stellar clusters and supernova remnants.