Planets form in protoplanetary disks surrounding newborn stars. As such, the most direct way to learn how they form from observations, is to observe them forming in disks. Thanks to a fleet of new instruments with unprecedented resolving power that have come online in the past decade, we have started to unveil features in imaging observations of protoplanetary disks, such as gaps and spiral arms, that may be associated with embedded (unseen) planets. By comparing observations with models of planet-disk interactions, the properties of still forming planets may be constrained. Such planets help us test planet formation theories. I will introduce the current status of this new field, and highlight some of the latest developments as well as unresolved problems.
