The 1970s is arguably the most fruitful and consistently excellent decade for horror cinema. Of course, that argument could be to extended that time period for cinema as a whole, and perhaps that’s why the 70s provided the breeding ground for so many of the genre’s greatest auteurs, enduring franchises, and singular creeptastic creations that altered and defined the course of horror movies to a track they remain on to this day. But if it was a time of cinematic revolution, it was also a time of cultural upheaval.

It was a time in which the mentality in America significantly darkened from the free-love optimism of the 60s. In its place, a harsh sense of reality arose. The horrors of the Vietnam war had seeped into the national atmosphere, both intimately in the homes of the millions of men and women who served, and on a massive scale where the war’s gruesome footage was constantly broadcast over the airwaves. Racial tensions were at a peak in response to the overdue social revolution of the Civil Rights movement. Nixon, Watergate, rising crime rates… American moviegoers were facing real life terror and strife on a daily basis and as a result, they were no longer moved to terror by gothic imagery, classic monsters, or character portraits of the damaged and insane. At the same time, the American censors opened the floodgates of violent imagery, resulting in an emergent aesthetic of realism and bloody, visceral violence that cut to the bone.

But America wasn’t the only nation experimenting and expanding their horror vocabulary. Overseas, Europe was also reaching new cinematic heights with their genre output. Perhaps most famously, the gruesome thrills and tightly-packed mysteries of Italy’s Giallo movement were at a height. In Britain, Hammer continued to deliver a steady stream of monstrous spine-tinglers in the studio’s last decade of mass-production, while smaller, more esoteric fare also made its way to audiences. Spain, too, had an exceptional horror movement despite still being under the rule of a fascist dictator for the first half of a decade.

Basically, anywhere you turn in the 1970s, you’ll the birth of legendary directors, cinematic movements in full swing, and first-rate horror movies galore as a generation of filmmakers pushed and prodded the boundaries of the genre. By exploring the endless permutations of subgenre allegory, those filmmakers took full advantage of the limitless opportunities for self-exploration, social commentary, and good old-fashioned meditations on mortality and the human condition. And they covered it all in blood and dirt and viscera.

Check out 21 of the absolute best from a brilliant decade below, and for additional lists check out our rundown of the best horror movies of the 80s and of the 90s.