DEF CON is one of the world's largest annual hacker conventions, held every year in Las Vegas, Nevada. The first DEF CON took place in June 1993. Many of the attendees at DEF CON include computer security professionals, journalists, lawyers, federal government employees, security researchers, and hackers with a general interest in software, computer architecture, phone phreaking, hardware modification, and anything else that can be "cracked." The event consists of several tracks of speakers about computer- and cracking-related subjects, as well as social events and contests in everything from creating the longest Wi-Fi connection and cracking computer systems to who can most effectively cool a beer in the Nevada heat. Other contests include lockpicking, robotics-related contests, art, slogan, coffee wars, scavenger hunt and Capture the Flag. Capture the Flag is perhaps the best known of these contests. It is a hacking competition where teams of crackers attempt to attack and defend computers and networks using certain software and network structures. CTF has been emulated at other cracking conferences as well as in academic and military contexts.