These pictures are of the MDF (Main distribution frame) in a telephone exchange. This is basically where all the wiring from the telephony and data equipment eventually ends up before going out on your line to your home / business.
These are the modern connectors:
To give a scale of the size (varies in each exchange):
Old style connectors:
Top of the frame:
I didn't include pictures of the DSLAM and MSAN's as these belonged to various providers. Essentially they will have cabinets with a HDF at the side.