Here are few facts about that track:
1- Built in 1965 in a no-flight zone. So nobody can make pictures, very smart
2- It's the world's largest test facility and the only one with a high speed circuit that has a 5.4 mile straight ( 8.7 km )
3- The straight portion of the track is perfectly flat and level for the entire length, when standing at one end of the straight you cannot see the far end due to the curvature of the Earth.