The vascular endothelium plays a vital role in the control of the circulation.It metabolises various vasoactive substances, converts angiotensin I to angiotensin II and secretes thepotent vasodilator prostacyclin, as well as nitric oxide and endothelin-1. The balance between thesemediators determines the response of the cardiovascular system in diseases such as hypertension, atherosclerosisand myocardial infarction. In this article I describe some of my work over the past 50 years. In theprocess, I hope to show that it is not only Princes who travel the road to Serendip but also Scientists.The application of simple methods, luck, happy coincidences, serendipity and noticing the unusual haveall played an important role in my scientific career. However, the choice of colleagues has also beenvital.

Keywords: blood bathed organs, endothelial cell, Pulmonary Circulation, Renin, snake venom peptides, ACE, Angiotensin I