West Register House, Edinburgh

This was one of the last buildings designed by famous architect Robert Adam, just a year before he died. Charlotte Square was faithfully built to his designs but this building, originally the St George Church, was simplified on the grounds of expense. It has recently been refurbished as West Register House and holds the Scottish Records Office documents, for which there is a search room. It features changing documentary exhibitions, and boasts the Declaration of Arbroath of 1320 on permanent display. Admission: is free.