LISBON, Portugal (May 20, 2021) The Spanish navy frigate ESPS Mendez Nunez (F-104), flagship for Standing NATO Maritime Group 2, departs Lisbon, Portugal, May 20, 2021 to participate in Exercise Steadfast Defender 21. Steadfast Defender is a defensive exercise based on an Article 5 scenario which is designed to deter aggression and respond to crisis if necessary. (Photo courtesy of the Spanish navy by Petty Officer Laura Pons Miles)