Solutions A tunnel carrying a stream under a road or railway has 4 entries with similar clues
- 7-letter words
- viaductStructure carrying a road or railway over a valley
- 14-letter words
- channel-tunnelA railway tunnel under the English Channel linking the coasts of England and France
- 23-letter words
- st-gotthard-road-tunnelThe world's longest road tunnel
- 25-letter words
- tunnel-at-seikan-in-japanThe world's longest railway tunnel