In this thesis we discuss multiple levels of aneurysm formation, from nationwide aneurysm data in the Netherlands we zoom all the way into individual cell characteristics. We look at abdominal aortic aneurysms, carotid artery aneurysms and other peripheral aneurysms such as femoral and popliteal aneurysms. At first we looked at the Dutch populations and show a convincing descent in the number abdominal aorta related deaths since 1980 discuss the possible mechanisms for this decline which only occurs in males. Better detection and management of aneurysms might be important, but trends in smoking most likely to be the cause of this trend. After this nationwide topic we focus more the tissue. We describe a new way to analyse histological tissue samples using our slideToolkit, which an important focus of this thesis. We created the slideToolkit as new software method to make fast, accurate an reproducible histological characterisation possible of fully digitised slides. In subsequent chapters we test, validate and use the slideToolkit and show that it is a versatile, powerful and free way to create meaningful phenotypic data sets. There is a need for accurate and reproducible histological characterisation, especially for subsequent analysis and interpretation fo data in association studies (like DNA/SNP comparison studies). In this thesis we discuss multiple levels of aneurysm formation, from nationwide aneurysm data in the Netherlands we zoom all the way into individual cell characteristics. We look at abdominal aortic aneurysms, carotid artery aneurysms and other peripheral aneurysms such as femoral and popliteal aneurysms. At first we looked at the Dutch populations and show a convincing descent in the number abdominal aorta related deaths since 1980 discuss the possible mechanisms for this decline which only occurs in males. Better detection and management of aneurysms might be important, but trends in smoking most likely to be the cause of this trend. After this nationwide topic we focus more the tissue. We ...