  The outskirts of galaxies - especially the very extended HI disks of galaxies
- are strongly affected by their local environment. I highlight the giant 2X-HI
disks of nearby galaxies (M 83, NGC 3621, and NGC 1512), studied as part of the
Local Volume HI Survey (LVHIS), their kinematics and relation to XUV disks,
signatures of tidal interactions and accretion events, the MHI - DHI relation
as well as the formation of tidal dwarf galaxies. - Using multi-wavelength
data, I create 3D visualisations of the gas and stars in galaxies, with the
shape of their warped disks obtained through kinematic modelling of their HI
velocity fields.
