Overview: Viewers learn about all sorts of tunnels, from road tunnels to tunnels that actually go underwater. We get to see actual construction of subway tunnels in Hong Kong.
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First Air Date: Jan 01, 1970Last Air date: Jan 01, 1970Season: 2 SeasonEpisode: 20 EpisodeRuntime: 10 minutesQuality: HDIMDb: 0.00 / 10 by 0 usersPopularity: 5.881Language: