It started with me looking out of a converted delivery van that had one side taken out and railings installed so that you could hold on and look at your destination. I looked out at the desolate grey skies to see there was wasteland either side of us and this gleaning, metallic city up ahead. I knew that no humans lived there. It had an 8 foot wall circling the whole city, which we smashed through. The van went down into a drainage system on the edge of the mechanical city, it then stopped and I and 5 other people, dressed in black, got out, we were all wearing army camouflage gear. As we headed into the tunnel we came to a massive collection of thick wires and pipes that were all heading towards the center of this robotic metropolis. One of the people broke a pipe and put in a small device which got sucked into the pipe. We then ran back to the van and drove out of the city, as I looked back at the structures on the horizon, I witnessed them disintegrate into a mushroom cloud.