Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean, overlooking the Strait of Gibraltar. The territory itself is a peninsula of 2.642 sq mi whose isthmus connects to the north with Spain.
The Google Map below shows the main road from Gibraltar into Spain which crosses the runway, from the map you can also see the pedestrians!
The Gibraltar Chronicle has posted an interesting article that describes the FOD situation, and the efforts required to control it. Read the article here.