BGP blackholing is an operational countermeasure that builds upon the capabilities of BGP to achieve DoS mitigation. Although empirical evidence of blackholing activities are documented in literature, a clear understanding of how blackholing is used in practice when attacks occur is still missing. This paper presents a first joint look at DoS attacks and BGP blackholing in the wild. We do this on the basis of two complementary data sets of DoS attacks, inferred from a large network telescope and DoS honeypots, and on a data set of blackholing events. All data sets span a period of three years, thus providing a longitudinal overview of operational deployment of blackholing during DoS attacks.