Few things show our social status as clearly as windows. From ancient stained glass to towering skyscraper, windows are the ultimate luxury item.
Writer and architectural historian Tom Dyckhoff tells the history of these holes in the wall.
Tom visits an Elizabethan mansion built when glass was as valuable than gold. He pushes up a Georgian sash window and handles the pulleys from 10 Downing Street. He speaks to an estate agent and finds out the cost of a south-facing window in the suburbs.
Standing in one of the world's tallest glass buildings, he asks what price we pay for a room with a view.
Producer: Hannah Sander.