The unique identifier of the related POI.
Pass it to the Place by ID service to fetch detailed information about the related location.
How this POI relates to the referenced one.
child: The referenced POI is contained within this POI (e.g., a store in this mall)parent: This POI is contained within the referenced POI (e.g., this store is inside a mall)
A reference to a related Point of Interest, in a parent-child relationship such as:
Example