London has a wealth of sights to keep its visitors occupied. But the British capital can also boast of some amazing wonders of engineering and construction, not all of which are so well known. Last time we covered the Monument which is definitely worth the effort required to climb its 311 steps.

Agreed, but it was quite a slog. So what’s next on the list?

More steps I’m afraid. But this time we’re descending, at least at first. And there’s only about a hundred. Oh, and there’s a lift too, although I’m not going to guarantee it’s working when you visit…

This isn’t Covent Garden tube station I hope?

Nope. That’s a few too many steps even for my liking. Read on…

The Greenwich Foot Tunnel

Image (c) Andy Higgs, Grown-up Travel Guide

The coolest way to cross the river…

Well, that looks kind of spooky…

Yes, a little. But the Greenwich Foot Tunnel is a really fun way to cross the Thames and is a real feat of engineering. It´s an underwater pedestrian tunnel in South East London designed by civil engineer Sir Alexander Binnie.

So how old are we talking here?

Not sure how old he was, but the tunnel opened on 4 August 1902, originally to allow south London residents to get to work at the docks and shipyards situated on the Isle of Dogs. This is now where the iconic skyscrapers of Canary Wharf are located (pictured below behind the north entrance) but at the time the original docklands were growing with the trade from the British Empire and the population of this marshy area had reached 21,000. “The Docklands” is now taken to mean the expensive housing that was built long after the area’s heyday.

Image (c) David Jones

More stats please!

The Greenwich Foot Tunnel runs about 15 metres under the River Thames between Cutty Sark Gardens and Island Gardens. It is approximately 370 metres in length and has an internal diameter of about 3 metres, so basically not very wide or tall. The cast-iron tunnel is lined with 200,000 glazed white tiles, which provide interesting acoustics and atmosphere.

Right, spooky…

No, but it can feel a little lonely when you’re down there on your own. The tunnel cost £127,000 to build (in 1902 money) which would probably just about buy a garage in Docklands today.  The entrance shafts are similar on both sides of the river and are capped by glazed domes, with lifts and spiral staircases allowing pedestrians to reach the sloping tunnel at the bottom. This is the southern entrance:

Image (c) Jim Linwood

The tunnel is classified as a public highway and therefore by law is open 24 hours a day, although the lifts do not always run the full time.

Yes, you mentioned that…

Indeed. They weren’t running when I was there, and I was on a Boris Bike. Navigating the stairs with that was not funny…

And you’re not allowed to ride down there either…

No, cycling is prohibited so you have to walk your bike. Anyway in theory  the attendant-operated lift service is open from 7am to 7pm on weekdays and Saturdays, 10am-5.30pm on Sundays, with no service on Christmas Day or Boxing Day.

Any other interesting factoids?

Er, the northern end was damaged by bombs during World War II. Repairs include a thick steel and concrete inner lining that significantly reduces the diameter for a short distance. This is the wonky part near the lift shaft where it’s even narrower. The Greenwich Foot Tunnel is handy for those exploring Greenwich (the town centre is close by the southern entrance, as are the Maritime museum, Observatory and the fabulous old tea clipper the Cutty Sark (which is currently under refurbishment after major fire damage). It’s then a convenient and fun way to reach Island Gardens on the opposite side, with Canary Wharf and modern Docklands (and indeed the wacky Traffic Light Tree) a little further north.

Okay, let’s have the details then.

You can reach the Greenwich Foot Tunnel from Cutty Sark Gardens, Greenwich and Island Gardens, Isle of Dogs. Take the DLR to Island Gardens or Cutty Sark station. Even better, use one of the boats on the Thames to reach Greenwich.

Admission free

Open 24 hours

More information including hotline for tunnel closures etc. at http://www.greenwich.gov.uk/info/200102/walking/693/foot_tunnels

Image (c) Jim Linwood