Complex sentence: Pall Mall is a street in the City of Westminster, London, situated in SW1 and parallel to The Mall, from St. James's Street across Waterloo Place to the Haymarket; while Pall Mall East continues into Trafalgar Square.
Split into simpler sentences: Pall Mall is a street in the City of Westminster, London. It is situated in SW1 and runs parallel to The Mall from St. James's Street across Waterloo Place to the Haymarket, while Pall Mall East continues into Trafalgar Square.