The stability and robustness of BGP remains one of the most critical elements in sustaining today's Internet. In this paper, we study the structure and stability of origin advertisements in inter-domain routing. We visualize and quantitatively characterize the frequency, size, and effect of address assignment and origin changes by analyzing realworld BGP updates for a period of one year from multiple vantage points. Broad classes of prefix behaviors are developed. We show that a significant portion of BGP traffic is due to prefix flapping and explore the contributing factors which include a number of prefixes with abnormal short upand-down cycles. A significant portion of prefixes have high origin stability. Most ASes are involved in few, if any, prefix movement events, while a small number of ASes are responsible for most of the origin churn. Additionally, we find that a high volume of new prefixes can be attributed to actively evolving countries, that some abnormal prefix flapping is most likely due to misconfiguration, and that some culprit ASes characterize the places where multi-origin prefixes oscillate.