This Epic-scale construction could be a munitions factory or even a bunker complex. It is the pinnacle of junk-based terrain building - I didn't pay for any of the building materials used in this piece!
The body of this factory is the inverted packing tray from a pack of Tesco's Cameos, which are mini ice lollies. I'm sorry if you don't have Tesco where you live - but I'm sure you could find something similar
Matchsticks
Mesh material from a dressmaker's oddments bin
Drinking straws and tubes from pens
Old capacitors from broken circuit boards
Thin card or plastic for the doors (I use old margarine tubs)
Plywood for the base plus sand, paint and a few left over Space Marine transfers
Glue the packing tray to a base of plywood or cardboard. Alternatively, cast several factories in paster of Paris using the tray as a mould!
Glue matchsticks around the perimeter as fence posts
Cover the base with sand. Scrape the sand away to make tracks and roads.
Snip the mesh material into strips and super-glue to the fence posts
Glue drinking straw bits, pen tubes, and capacitors to the roof to make smoke stacks
Make a little pile of pipes from drinking straws
Embellish as you wish - I used the Imperial eagle motif from a Space Marine banner pole
Spray the whole thing black
Paint up the model. This one is concrete grey with silver domes. I shall make some in camouflage colours too. To paint the mesh fencing, place some newspaper behind to support it whilst brushing.
Add Space Marine transfers
Why not buy some Epic gun turrets and make a fortified factory complex?