Two Greek coast-guards go through their daily routine in a coast-guard wheel, at Marina Zeas, in Athens, Greece, June 8, 2018. The search and rescue operations of thousands of migrants crossing the Aegean Sea, along with combating the illegal trade circuit are among the top priorities and challenges for the Greek Coast Guard, a Greek official told Xinhua here. (Xinhua/Marios Lolos)TO GO WITH Feature: Migrant rescue operations, illegal trade top challenges for Greek Coast Guard