Flying from Bautimi in the South, this is a low level flying and navigation mission for two Hawks simulating the famous Mach Loop
The Mach Loop is a set of Welsh valleys, situated between Dolgellau in the north, and Machynlleth in the south (and from which the Mach Loop gets its name), which are regularly used for low level flight training, with flying as low as 250 feet (76 metres) from the nearest terrain.
If you want to see what it looks like in real life, and DCS check out this video:
For more information on the Mach Loop go here: http://machloop.co.uk/
Yes, I know DCS World doesn't have any Welsh valleys but, and I can speak from experience here, any valley at 250ft and 500kts looks pretty much the same.