In recognition of World Oceans Day, Annual Reviews has curated a collection of articles that review the topics of marine pollution, human impact and environmental stewardship, and marine species' adaptation. Nano- and microplastics are polluting the food chain from the bottom up. Harrowing images of marine wildlife entangled in, or ingesting, the plastic debris in our oceans serve as stark warning of the impact humans are having on the environment. These images are increasing in prevalence, but today is a great day to mobilize for change. FREE ONLINE ACCESS THROUGH JULY 31, 2018 and always available at subscribing institutions.