I've compiled a map of underground tunnels in Washington DC, please take a look: https://www.google.com/maps/d/viewer?mid=1sODx5pIhUix0wUaS2xbe6aYLw3U

The ones under The Capitol and the WH look like this: https://www.youtube.com/watch?v=U-t37HYTNro

We should look underground if we want to fully understand how these mundane creatures operate. Please send new tunnels with references in the comments and I'll update the map. I bet a dinner there is some reference somewhere to a tunnel right under Comet Ping Pong