  The flat spectrum radio quasar PKS 1510-089 is a monitored target in many
wavelength bands due to its high variability. It was detected as a
very-high-energy (VHE) $\gamma$-ray emitter with H.E.S.S. in 2009, and has
since been a regular target of VHE observations by the imaging Cherenkov
observatories H.E.S.S. and MAGIC. In this paper, we summarize the current state
of results focusing on the monitoring effort with H.E.S.S. and the discovery of
a particularly strong VHE flare in 2016 with H.E.S.S. and MAGIC. While the
source has now been established as a weak, but regular emitter at VHE, no
correlation with other energy bands has been established. This is underlined by
the 2016 VHE flare, where the detected optical and high-energy $\gamma$-ray
counterparts evolve differently than the VHE flux.
