SolarmovieOne

Watch Sydney's Super Tunnel Season 1 Episode 3 online — it may be available on legal streaming platforms such as YouTube, Netflix, Prime Video, Hulu, Disney+, and others.

Another super challenge looms, perhaps the greatest of the entire project - digging two tunnels beneath Sydney Harbour.

In the early planning stages, the team actually considered dropping pre-fabricated tunnel sections down onto the floor of the harbour one by one, lowering them from barges, which was the way the road tunnel under the harbour was built.