The (now yearly) NATO CCDCOE International Live-Fire Cyber Defence Exercise monikered 'Locked Shields' began on April 10th, 2019, and is currently live. If you can attend, do not hesitate to do so (by invitation only). Read all about it.
"The annual real-time network defence exercise is a unique opportunity for national cyber defenders to practise protection of national IT systems and critical infrastructure under the pressure of a severe cyberattack. It is a Red team vs. Blue Team exercise, where the latter are formed by member nations of CCDCOE. The participating Blue Teams play the role of national cyber rapid reaction teams that are deployed to assist a fictional country in handling large-scale cyber incidents and all their multiple implications. In addition to maintaining nearly 4000 virtualised systems while experiencing more than 2500 attacks, the teams must be effective in reporting incidents, executing strategic decisions and solving forensic, legal and media challenges." via the NATO Cooperative Cyber Defence Centre of Excellence (CCDCOE)