For those lucky enough to live in England, next week there are four days (9-12 Sept) of "Heritage open days" where places are open to the public that normally charge a fee. There are also local heritage tours/walks organised.

There are over 4,000 events. The website is http://www.heritageopendays.org.uk
or http://www.heritageopendays.org.uk/directory/ for the directory of events.

However when I tried to access it, it was painfully slow.

The National Trust is opening almost 200 properties for free, though only on 11/12 and some only for one of those days.

See National Trust | Events | Heritage Open Day Participants

Or go to the main National Trust web site and type in Heritage days into the search.