  Planet formation is thought to begin with the growth of dust particles in
protoplanetary disks from micrometer to millimeter and centimeter sizes. Dust
growth is hindered by a number of growth barriers, according to dust evolution
theory, while observational evidence indicates that somehow these barriers must
have been overcome. The observational evidence of dust traps, in particular the
Oph IRS 48 disk, with the Atacama Large Millimeter/submillimeter Array (ALMA)
has changed our view of the dust growth process. In this article I review the
history of dust trapping in models and observations.
