Things fall apart; the centre cannot hold;

Mere anarchy is loosed upon the world,

The blood dimmed tide is loosed, and everywhere

The ceremony of innocence is drowned;

The best lack all conviction;

While the worst are full of passionate intensity.

This is from The Second Coming by William Butler Yeats

The quote is also beside Pablo Picasso's painting of Guernica at the Reina Sofía Art Museum in Madrid

https://www.poetryfoundation.org/poems/43290/the-second-coming