Drive around drought-devastated Northern California and you will invariably see cars with “Stop the Tunnels” bumper stickers. “Stop the tunnels” has also become a rallying cry in the United Kingdom, where politicians in London are scrambling to halt the sudden free-flow of immigrants using the Channel Tunnel to pour into England from Calais, France.

Migrants outside the Eurotunnel area, in Calais, northern France, last week. More than 3,000 migrants have tried to storm the area surrounding the Eurotunnel in an attempt to enter Britain.

Two very different challenges related to age-old subterranean engineering solutions meant to transport resources from one place to another. Whether those resources are water, goods or people, tunnels are back in the news. Read more