The south side of the Magnet House, also known as the Magnetic Observatory, of the Royal Observatory, Greenwich. It is sited in the gardens between the Altazimuth Building and the South Building. Unusually the building is constructed entirely of wood. On the side of the building is a small sign advising "Bicycles are not to taken past the Magnet House". The Altazimuth Building is in the background. A masked negative.