There used to be a big black splodge from an oil well spillage in the Empty Quarter that was shown on a Topo in the 1970s. I saw it in 1977 from a Viscount from Muscat to Sana'a.
We also saw two camels and Bedouin Arabs in the middle of nowhere. Nothing to be seen in any direction but I guess they knew where they were going.
It's called "The Empty Quarter", for a reason.