FACTOID #53: If you thought Antarctica was inhospitable, think again - its land area is only ninety-eight percent ice. Reassuringly, the other 2% is categorised as "barren rock".
In biology, RER is the abbreviation for rough endoplasmic reticulum.
The RER network truly came into being on December 9, 1977 with the joining of the Nation-Boissy and Auber-Saint-Germain-en-Laye segments as the eastern and western halves of the RER Line A at the just-completed hub station of Châtelet - Les Halles in the heart of Paris.
The abbreviation RER is commonly used to describe the urban rail network currently being planned for the Brussels region and for major cities in Switzerland.