Two days until Open House Weekend, the premier event in London's architectural calendar. With bit noticeably chomped and anticipation status set to 'moist', we round up our highlights from previous years. Please, please, we want your suggestions in the comments. Diligent and dogged though we are in our exploration of the capital, there are over 600 places in the listings, and we know there must be plenty of what the guidebooks always call 'hidden gems' that we don't know about.
CENTRAL
Freemasons Hall, 60 Great Queen Street
AKA Spooks HQ.
Gibbs Building, 215 Euston Road
Swish headquarters of the Wellcome Trust, including what must be the UK's tallest indoor sculpture.
HQS Wellington, Embankment
Floating livery hall for the Guild of Master Mariners. Gold leaf and plush finery bobbing on the Thames: probably needs an expensive insurance policy.
Linnean Society, Burlington House
Caught between the 300th anniversary of Carl Linnaeus' birth (1707) and 200 years since Darwin breathed his first (1809), this is a relatively quiet year for the learned society that deals with biological taxonomy. See the stunning library and learn more about the key figures of botany and evolutionary science.
Royal Institution, Albemarle Steet
While we're talking science, head over to the big daddy of learned societies in Mayfair. The RI just reopened its doors after an extensive and expensive refit. Check out the plush new look, and superb dining facilities.

Royal Society for the Encouragement of Arts, Manufatures and Commerce, John Adam Street
The RSA holds many open days and public events, but it should be visited for the variety of rooms on offer - from catacomb-like basement areas to the magnificently painted main hall.
St Anne's Tower, Soho
Been there, done that, got the chest infection. Climb the spire that health and safety forgot, before they ban this feat of death defiance.

Westminster Hall
Probably London's most historic building, after the Tower. This is an absolute must-see if you never have.
CITY
Bank of England Tour
Of all the buildings we've ever explored for Open House, this has more tales to tell than any other. Get there before opening time, as queues grow long.
City Marketing Suite
Easily overlooked, this 3-D model of the capital can be found on Basinghall Street right next to Guildhall. Splendid.
Guildhall
Relatively mainstream destination, but definitely worth a look if you've not been before, especially if you like heroic sculpture. As well as the main hall, check out the crypt, Roman amphitheatre and adjacent gallery. Queues are usually short.

Lloyd's of London
Now here the queues get excessive, but the inside-out insurance firm is a true must-see of Open House.
Old Turkish Baths, Bishopsgate Churchyard
Subterranean pizzeria in an ornate Victorian gem of a building. Look out for the photos of the owner pictured with various celebrities on the walls.
EAST
Balfron Tower, Poplar.
Trellick Tower's lesser known sibling, by maligned architect Erno Goldfinger.
Institute of Cell & Molecular Science, Whitechapel
Gaze down on a laboratory for a giant orange pod. Utterly unique building and highly recommended.

One Bishops Square
Utterly bland Foster building offers impressive view of Spitalfields from sixth-floor roof terrace. Also, look out for the Charnel House in Bishops Square. And missing apostrophes.
Wilton's Music Hall
Epically unrestored Victorian knees-up venue that may just collapse around you while you're pretending to be Marie Lloyd.
WEST
Hoover Building, Western Avenue, Perivale
London's finest Art Deco building. Includes a Tesco, sadly.
Ismaili Centre, Cromwell Gardens (near V&A)
Learn about a religious community you've probably never heard of, while admiring the views from the stunning roof terrace.
Lindsey House, 100 Cheyne Walk
17th Century pile, notable for its stellar cast of former residents, including Whistler and Brunel (and Thomas More, sort of).
Shri Swaminarayan Mandir
Preposterously magnificent Hindu temple crafted from marble and limestone. If you've never seen this, put it to the top of your list.
SOUTH
City Hall and More London
Glass, glass, but not much class. Still, the Mayor's testicle offers some of the best views in the capital from 'London's Living Room'.

Lambeth Palace
The Archbishop of Canterbury's London home is one of our city's A-list buildings, but is rarely listed as a place worth visiting. Particularly good if you like old trees.
Peckham Library
London's best example of what will sure come to be known as the 'misguided Tetris' school of architecture.
Severndroog Castle, Shooters Hill
Rare chance to ascend this dilapidated 18th Century folly near Blackheath.
William Booth College, Champion Park
Discover a lesser-known edifice from Giles Gilbert Scott, architect of Battersea and Bankside (Tate Modern) Power Stations.
All images by M@.