This is an art project called 'Standard Time' by Mark Formanek. In late 2007, with funding from the German Foundation for Arts & Film he hired a team of 70 workers who constructed this 4 x 12 m clock in real-time over a period of 24 hours in Berlin's Sculpture Park. The first construction (as well as subsequent, shorter builds done for various events) is the first part of the performance, the second is the display of the video synchronised to local time. which has been placed in a number of galleries. Formanek has received a fair bit of attention and acclaim for this as it was quite original and very well-executed.

You can get more details as well as downloads such as an iPhone app at the official site: standard-time.com. For those interested in how it was done, the site also has a short documentary on the process.