Subterranea Britannica (or Sub Brit) is a fantastic website for explorers of forgotten or obscure underground urban landscapes in the UK - they have a huge collection of photos of abandoned tunnels, mines, military bunkers, and more.
This one above is from an article about Underground London, where a large network of "pipe subways" lie beneath the ground, unbeknownst to the citydwellers.
The feeling of disappointment soon gave way to one of admiration when we walked along the subway and the uses of the various pipes which ran along one side were pointed out to me. They include the mains of the gas, New River, hydraulic power and electric light companies, also the pneumatic tubes and hundreds of wires belonging to the GPO and the arrangements whereby the service mains are connected to the various houses show that simplicity which constitutes the high water mark of mechanical ingenuity. The usual time for making the connection is half an hour and in case of non payments of rates, a house can be cut off from its gas, water, electric light or power supply in a few minutes and this moreover, without the unfortunate tenant or the general public knowing anything about it.