3 ms·
Mine was more along the lines of how deep would the tunnel have to go.
by zeristor 4y ago
Mine was more along the lines of how deep would the tunnel have to go.
- Arnt 4y agoAbout 200m, which is considerable but nowhere near a record, the deepest being 290m deep IIRC. It also doesn't have to be steep. 200m down in 10km is just a 2% incline.