For one weekend in September around 750 buildings, new and old, open their doors to visitors. Many are usually closed to the public. And do you know what the best part is? It's all free. Yes, all buildings, usually including the London Eye (at selected tour times), are free for us to enjoy.

The aim of Open House London is to encourage us all to recognize good architectural design and to explore buildings and be able to appreciate what good design means.

(Note: 'Open House' are now calling themselves 'Open City' but it's the same event.)

Open House London Buildings Guide

Open House London Weekend. Not only does it have the building's addresses and information about each site, but the Guide also includes such important information as nearest tube stations, opening times, disabled access, and even which buildings are likely to have long queues. You can buy the Guide online for £6.50 from early August.

What they don't tell you is that you can pick up a copy of the Guide for free from all London public libraries. The Guide is available to buy/download/pick up from mid-August as Open House London is always on the third weekend in September and many buildings have tours you need to pre-book.

Planning for Open House London

Check the dates for this year and the Open House London Basics.

It's important to get hold of a copy of the Open House London Buildings Guide early (from mid-August) so you can pre-book the tours that really interest you as they have very limited places.

Not all places need to be booked so it's best to go through the Guide marking your faves and then try to make as many bookings are possible. Once you've got some bookings you can plan your days with the other buildings you want to see that are open all day.

Check the Open House website a few days before the event as any withdrawals of participating buildings will be listed, so you don't have a wasted journey.

Essential Equipment

Just as you would for a London walking tour, wear comfortable shoes and don't take a huge bag as you'll be carrying it all day. Along with your copy of The Open House London Guide, you'll need an A-Z, a Travelcard for hopping on and off tubes and buses, and a bottle of water.

Personal Recommendations

Open House London includes such diverse buildings as offices, residential homes, sports clubs, and government buildings.

I love this event and have visited many unusual buildings over the years. Some of my personal favorites have been:

• Canada House (Takes up the west side of Trafalgar Square)
• Freemason's Hall
• Sir John Soane's Museum (Although this is open throughout the year)
• Bank of England
  This has a fantastic tour and the queues move quickly so don't be put off.
• Society for the Protection of Ancient Buildings (A 1740s Huguenot silk merchant's house)
• Government Art Collection
  A chance to see the government-owned artworks that are not on display in government buildings.
• Brixton Windmill
  Who would have thought you'd find windmill from 1816 in Brixton?
• Wimbledon Windmill
  I think I just love the idea of windmills in London!
• 15 and a half Consort Road
  An amazing home with an opening roof and a sliding bath.
• Jewel Tower
  Built in 1365 and part of the Palace of Westminster - used as the ticket office for the Houses of Parliament Tour
• Mansion House
  Residence of the City of London's Lord Mayor.
• St. Martin-in-the-Fields
  One of Britain's finest churches in Trafalgar Square.
• St. Anne's Tower
  An interesting tower in the heart of Soho.
• William Morris Society - Kelmscott House
  Again this is open outside of Open House London.
• St. Botolph's Aldgate
  I was taken to the bell tower and watched English bell-ringers.
• Guildhall and the Guildhall Art Gallery and Roman London's Amphitheatre

The places I really want to see, but never book in time for, are:

• The Willis Building
  Distinctive stepped formed glass structure. Surpasses statutory carbon reduction targets by more than 20 per cent.
• The Gherkin
  One of the latest London landmarks to grace the skyline.
• Centre Point
  Over 30 floors in the center of the West End, overlooking Oxford Street.
• 2 Willow Road
  Unique and influential Modernist home from 1939.

I'd love to see inside Lloyd's of London too but there are always hundreds of people in the queue by 10am on the first day so I always give up.