Complex sentence: He ran it on a circular track just south of the present day Euston Square tube station in London, whose site in Bloomsbury has recently been identified archaeologically as that occupied by the "Chadwick Building", part of University College London.
Split into simpler sentences: He ran it on a circular track just south of the present day Euston Square tube station in London. The site in Bloomsbury has recently been identified archaeologically as that occupied by the "Chadwick Building", part of University College London.