The big day out

The annual Open House weekend is your chance to tour some of the 600 public and private buildings involved.

The Gherkin is off the list this year, but notable newcomers include the Wellcome Trust's Gibbs Building on Euston Road and Queen Mary College's Institute of Cell & Molecular Science in the East End - both worth the trip for their artworks as well as their bold construction.

But this is not just a weekend for contemporary architecture fans. Founder Victoria Thornton's key aim is to showcase all eras, provided they pass architectural muster, so bingo halls and post-war public housing make the list alongside medieval churches and Georgian mansions.

The OpenSite initiative unveils works in progress - notably Heathrow Terminal Five.

www.londonopenhouse.org. Sat 17 & Sun 18 Sept, various times. Free.