Up to 25,000 people are expected to take part in Dublin’s Open House event this weekend.
The three-day event allows people to tour areas of Dublin that are not usually available to the public and have a unique architectural style, such as the Provost's House, Sean Treacy House and Leinster House.
A total of 100 buildings are allowing tours for the weekend, which attracted 23,000 people last year.
Despite many buildings requiring pre-booking, the majority of tours are on a first-come, first-served basis, allowing people who are interested in the tours the chance to take part.
There will also be 30 additional events to celebrate the event, such as walking tours of the Docklands, Dublin Zoo and Temple Bar. These events are free to attend.
So far, one of the most popular tours is of Donnybrook Bus Garage, says event spokeswoman Annette Nugent.
"There is a lot of interest in the bus garage. It has a structurally innovative vaulted concrete roof, which is arguably one of the first of its kind in Europe. There is no booking required for this tour as well, so people who hear about it during the day can come along," she said.
"The tours that are fully booked are mainly of residential properties. The Criminal Courts of Justice and Busáras are attracting a lot of attention too though."
The Criminal Courts of Justice building was completed in 2009 and won the Opus, Design and Construction Excellence Award in 2010. Building work started on Busáras in 1946 and was completed in 1952.
Last month at the event's launch Nathalie Weadick, director of the Irish Architecture Foundation, which organises the annual event, said that Open House Dublin is an important event for the architectural community in Ireland.
"Open House Dublin is the biggest festival for architecture in Ireland and continues to draw crowds who are passionate about their built environment and who are inspired to know more," she said.
Full information on building and walking tours are available on openhousedublin.com.