Valencia GP Track
This is a fairly new track that found its place on our list because of financial misfortune. It was built in 2007 and was used for 5 years as the F1 GP track. Due to a failure to negotiate a deal with the F1, the owners soon had to bail and the track was abandoned in 2015. Quite a shame considering its age and the fact that it could easily be re-purposed if only there was a willing investor.