Guichet: blood pressure and hypertension

Hypertension is one of the most widespread chronic diseases in the world. It's an insidious disease because it's silent; you don't feel any particular effects for a long time. Hypertension affects 1.5 million people in Switzerland and, according to the WHO, 1.3 billion people are affected by uncontrolled hypertension. What is hypertension, how is it detected? How is it controlled? How is it treated?