If the title of this post doesn't explain what's going on right now on Shoreditch High street, then maybe the press release from TFL will:

An extraordinary engineering feat is due to take place in the heart of the city this weekend, to help complete a crucial section of Transport for London?s (TfL) East London line project.

Britain?s biggest mobile crane is being brought in to pick up and then gently lower into place a massive 350-tonne bridge over Shoreditch High Street. The bridge will carry the East London Railway over the busy City thoroughfare, when work to extend the line is complete.

The full operation to secure the bridge in position will last the whole weekend, with the actual lift-and-drop taking place on Saturday morning.

As we type, the 35m long bow-string bridge (named, apparently, after its resemblance to an archer's bow) is being manoeuvred into place by the 1200 tonne crane. If you want to get down to Shoreditch to see the manoeuvrings though, you'll have to be quick ? it seems that much of the excitement may have already passed.

For the more lazy amongst us, TFL is streaming the proceedings via a live webcam (which, at the time of writing, appears to have just gone down ? oh well).

Picture of an un-bridged Shoreditch High Street courtesy of Danny McL's Flickr photostream. If anyone gets any good photos of the actual manoeuvrings, please let us know!