@ The Ghost Bus Tunnel.
 
Under a busy road in a busy Belgium city is a disused, unfinished metro tunnel. (Appox 2.5KM long)
It now is used as a graveyard / holding tank for old trains & trams !
 
Here is a funny story....
We parked up on a side street, found the entrance and hit it ! Over an hour had past exploring these epic underground tunnels when we decided to leave.... Upon returning to my car, I clicked the button to unlock it and realised it wasnt locked ?! Then I walked around the side to get in and noticed 2 windows had been smashed and the car ransacked ! ( The list of damage ranges from Trev's Primark trousers to Kev's bloody passport ) 
 
Nice.