What are the three kinds of routed events in WPF and how do they differ?

Routed events in WPF are direct, tunneling a bubbling. A direct event can be raised only by the element in which it originated. A bubbling event is raised first by the element in which it originates and then is raised by each successive container in the visual tree. A tunneling event is raised first by the topmost container in the visual tree and then down through each successive container until it is finally raised by the element in which it originated. Tunneling and bubbling events allow elements of the user interface to respond to events raised by their contained elements.