The East End of London was formerly a very impoverished area, filled with slums and disease. Some of the worst slums, called "rabbit warrens" or "rookeries", had walls so deteriorated that they could be entered through holes. While some tenement flats were later built to replace the slums, they too deteriorated into slums over time. The document then describes some former streets and areas in the East End, including Black Lion Yard, Old Montague Street, and Valance Road. It mentions clubs and community centers that used to exist, like the Brady Club. The East End has since undergone significant changes, with many flats built and many residents moving away to other areas like Il