Quote:
Originally Posted by PR_Glen
anything big happening warranting filling it will just make it the worlds largest tomb in seconds.
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Every 325 meters there are a series emergency escape tunnels marked with easy open fire/gloodproof doors that lead to service tunnels that exit out multiple opens throughout the length of the tunnel. http://www.swissinfo.ch/eng/alptransit_engineers-meet-challenge-of-gotthard-tunnel/40792690