First off, almost all grape wine varietals in the world of which there are now about 1,400 (don't trust wikipedia's claims between "5,000-10,000" which, come on, is a bizarrely wide range), are made from the grapes of a single species called Vitis Vinifera.
So how did all those varieties come about? Well, the Vitis Vinifera had been domesticated for thousands of years (earliest evidence is 6000 BC) so its cultivation meant there was a great chance for cross pollination.
One of the world's most famous cross pollinations is of the (Left pic) Cabernet Franc and the (Right pic) Sauvignon Blanc, producing the now famous Cabernet Sauvignon which originated in the vineyards of Bordeaux, France during the 17th Century.
It became a very popular variety initially because of its thick skin and hardy vines which led to natural low yields and late budding making it resistant to rot and insects. Vineyards the world over started planting Cabernet Sauvignon and it became the most popular varietal until Merlot overtook it.
For the longest time, many mythological stories surrounded this grape varietal until the UC Davis scientists killed the romance by sequencing the genome of the grape. So the other unimportant trivia about the Cabernet Sauvignon grape is that it is the first genome of a commercial wine-producing grape to be sequenced.
It is usually noted for aromas of black pepper, green peppercorn, bell pepper, mint and eucalyptus depending on the climate it was grown. It is also hard to distinguish between a Merlot and Cabernet Sauvignon sometimes because both have Cabernet Franc as a parent.
One of the poorest places in the world due to its inhospitable soils and dry weather, Ningxia, China produced an award winning Cabernet Sauvignon in 2010.
I think that has been more than five facts that you could have done without.