If you look at older maps, there is a land route connecting qatar with UAE. What happened to it? well, one day the saudis decided they would take it over, and did so, murdering some qatari border guards in the process.
http://www.arab.de/arabinfo/qatar-government.htm

When I lived in Oman, the same sort of thing happened to a piece of land bordering the UAE...which is why Oman is split in two pieces.