We had a very easy 30 km bike ride today, along mostly gravel forestry roads and old dismantled railway tracks. At about the half way point, we went through a disused railway tunnel. It is 1.4km long and the fifth longest walkable tunnel in the world. It took 2 years to build from 1891-93. Most of the tunnel is concrete block, apart from a short section of brick. Construction was started at either end and when they met, it was only 8mm out of alignment. It must've been a massive job way back then to construct this tunnel and incredible how accurate it was!
