This paper demonstrates the MobilityDB moving object database system. It is an extensive implementation on top of PostgreSQL and PostGIS with multiple novel aspects. MobilityDB defines multiple spatiotemporal types for moving geometry and geography points, as well as for temporal integers, reals, Booleans, and strings. It also defines a rich set of operations on these types. The types are supported with spatiotemporal index access methods by extending GiST (Generalized Search Tree) and SP-GiST (Space Partitioning GiST). The query interface is SQL. MobilityDB thus extends the PostgreSQL optimizer with statistics collectors and selectivity estimation functions. It is available as open source. The demonstration includes a scenario with multiple queries, and a publicly accessible query interface on the Web.