I’ve had a few couples that really love to travel, and love incorporating this idea into their ceremony.
The idea I’ve had a couple different couples is to have a map on an easel, either of a certain place (i.e., place where they got engaged/married/live), or the country, or the world. The map can have markers on it already of places they have been to already as a couple, and during the ceremony they can add markers to places they want to go. The markers of where they have already been would be in one color, and the ones for the places they want to go still would be in a different color.
Or, they can just add a marker to the place where they are currently getting married, and tell guests that as they go places, they will add their markers to their map.
The actual map can be of so many different materials: metal/magnetic with special magnets for markers, cork and push pins, wood and maybe using permanent markers or pre-made vinyl markers. You get it: the possibilities are endless!