This map was made in 72 Hours for a jam, It is based around the Frontline theme which is a community pack (http://frontline.tf/)
The aim of the map was to make a fun, intense city themed map.
Players must escort a payload full of priceless paintings to the helicopter then they are taken away.
It is currently in the top 5 of the most popular maps of all time on the TF2 Workshop page.