Short answers, pulled from the story.
The name Hertfordshire derives from the Anglo-Saxon phrase heort ford, meaning a deer crossing of a watercourse. The name is first recorded in the Anglo-Saxon Chronicle in 1011, and deer continue to feature in many of the county's emblems.
Saint Alban was a Romano-British soldier who was beheaded on Holywell Hill in what is now St Albans around 293, making him the first recorded British martyr. He took the place of a Christian priest he was sheltering and is the Patron Saint of Hertfordshire; his martyr's cross, a yellow saltire on a blue field, appears in the county's flag and coat of arms.
The Hatfield rail crash occurred on the 17th of October 2000, killing four people and injuring more than 70. The crash exposed shortcomings in Railtrack's maintenance regime and led to extensive speed restrictions and major track replacement across the national rail network.
The first three Star Wars movies, Episodes IV, V, and VI, were filmed at the Elstree studios complex in Borehamwood. American director Stanley Kubrick also used those studios and lived in the surrounding area until his death.
Letchworth, in the far north of Hertfordshire, became the world's first garden city in 1903. It also hosted the UK's first roundabout and the first planned Green Belt in Britain, making it a global prototype for planned town design.
The Lee Valley White Water Centre in Waltham Cross, Broxbourne hosted the canoe and kayak slalom events at the 2012 Summer Olympics. The venue, opened in 2010, features a 300-metre Grade IV Olympic course and a 160-metre Grade III legacy course, and has since hosted the ICF Canoe Slalom World Championships twice.