Do you like tunnels and trains? Look this combination in Klevan, Ukraine. A very small city close to Rivne. Once i went there to walk along six kilometers in length.
1) How to get there?
Go to Rivne and show to a Ukrainian the words "Тунeль Кохaння", or speak Russian or Ukrainian
2) It's free?
Yes
3) The train pass through the tunnel?
Yes, but not always