Ever heard of Brixton’s windmill, or wondered what is inside the iconic Battersea Power Station? Now’s your chance to find out!

Londoners are in for a treat this weekend, with the highly-anticipated Open House event – a unique opportunity to see, explore and learn about amazing architecture and design in your area and across London over one weekend.

More than 800 buildings of all kinds will open their doors across London, alongside a programme of neighbourhood walks, engineering and landscape tours, cycle rides and experts’ talks. And the best part? It’s all for free!

This year’s theme ‘Celebrating architecture, people and place’ explores issues that are relevant to local communities and how the architectural environment is evolving – including the design of homes, the impact of climate change and the role of architects and contemporary design.

When is it? September 21st and 22nd 2013.

Where can I see a list of participating buildings? On the Openhouse.org website, which has information on all the 800 buildings taking part. 

Our top picks:

Battersea Power station
Built in the 1930s as a coal-powered fire station and powering over one fifth of London at its peak, Battersea Power Station is participating in the event for the first time. It’s the last opportunity to see one of London’s most iconic buildings before it undergoes an eagerly anticipated redevelopment with shops, cafes, restaurants and bars set amongst 3,500 new homes and 18 acres of green space. A must-see! First come basis; queuing if necessary. Project architects, engineers and landscape architects are available on site.

30 St Mary Axe (aka the Gherkin)
One of the capital’s most-recognisable skyscrapers, The Gherkin (as it is affectionately known) is a 40-storey office building in the heart of London's financial centre. The  RIBA Stirling Prize Winner (2004) boasts impressive 360 degree views from its curved peak. Visitors will be able to tour the landmark every 30 minutes and learn about its design and green construction, enjoying the great views along the way. Groups of 30 people every 10 mins; strictly 20 mins duration in total, on a first come basis.

Brixton Windmill
Who knew there was a windmill in Brixton? Another highlight, Brixton windmill is one of the only surviving reminders of the district’s agricultural past, years before the famous Electric Avenue was built. The present brick tower windmill was built in 1816 when Brixton Hill was open fields and was a working mill until 1934. It has since been restored to working order in 2011. Visitors can hear the intriguing story of the Ashby family, see the original wind-powered machinery and find out how it was once used to make stoneground flour. Half-hourly tours; duration 40 mins; max 3 people per tour; pre-book only on 07587 170 029. 'Short' tours to the first floor are on a first come basis; duration 20 mins; max 6 people per tour.

Lloyds of London
Another of London’s contemporary masterpieces, like Richard Rogers' Pompidou Centre in Paris – the architects Lloyds of London building is home to the world's leading insurance market and is a key example of British High-Tech architecture. First come basis, queuing if necessary.