Fancy a trip up the BT Tower? How about Centrepoint? Maybe London Underground's art deco headquarters at 55 Broadway? These and many other venues will be open to visitors over the annual Open House weekend (18-19 Sept), now redubbed Open City. Most places will be truly open - just turn up on the day and take a look around. Some of the more interesting, however, need booking in advance - and that includes the three listed above. Phone lines and email bookings open at 10am this morning (visit this microsite, which goes live at that time), with places at the more popular venues likely to go quickly. In an heroic act of generosity, IanVisits has mapped all the places that you need to book for. These and everywhere else are listed in the Open City guidebook, which is available now through the web site. See you at the top of the BT (fingers crossed).
Update (10:43): Most of the famous venues are now booked up. Open House initially gave the wrong link - you need this one.