Ethernet Wiring Through Hostile Territory?

GoogleDidntFindIt asks: "I need to connect a terminal to a server which contains very sensitive information. Unfortunately, the terminal is about 200 feet away from the server. The server (which even includes a 'self destruct' device) and terminal are both in highly secure areas of the building, but the wiring will be in uncontrolled areas. What should I do to keep people from tapping or monitoring the wire?" Is there any way a conduit can be wired with an alarm which goes off when it's integrity has been violated?

"Heres a basic description of my situation:

• A new wire/fiber/cable/whatever will be run and I can use any sort of conduit I want.
• A potential attacker may have several days of undetected access to parts of the wire/conduit and may have sophisticated fiber-optic tapping equipment (which can tap a fiber without cutting it).
• I can physically inspect the conduit/cable/wire once a month.
• Ideally, the system would also notify me of a majority of successful attacks (or, even better, disconnect the line).

I'm aware of IPSEC and other encryption systems, but they aren't suitable for this project - I'm looking for systems which address physical security and protect against traffic analysis."