Number 19: Hardcore Punk

Hardcore punk (also called hardcore) is a genre related to punk rock that usually tends to be faster, thicker, heavier and more abrasive. It's closely linked with the straight edge movement, a subculture based around not using drugs, though it can also extend to being vegetarian/vegan, not being promiscuous and avoiding caffeine or similar things. The term 'straight edge' came from a song by Minor Threat, a 1980s hardcore punk band. Many hardcore punk bands are also associated with left-wing politics, particularly the earlier bands.
Unlike other punk genres, hardcore punk tends not to be associated with dress styles such as safety pins, spikes, patches etc. The musicians (and therefore their fans) follow a more dressed-down style: jeans, tees and crewcuts. Another interesting difference in hardcore punk is that it's often described as having it's own unique form.
The aforementioned Minor Threat are a famous hardcore band, though they only stayed together for three years. Despite this, however, it had a huge impact upon the genre. They strongly influenced the straight edge subculture along with a DIY view towards music distribution and concert promotion.
Another band that is linked to this DIY theme is Black Flag, who disbanded in 1986 but are still well-known within the genre. Their songs generally had strong non-conformist and anti-authoritarian messages.
Warning- these songs may contain swearing :P

Damaged- Black Flag

Straight Edge- Minor Threat