Katy Perry Visits Auschwitz: ‘My Heart Was Heavy Today’

While in between shows on her European tour, Katy Perry paid a visit to concentration camp Auschwitz-Birkenau in Poland.

The “Dark Horse” singer, 30, stopped by the World War II landmark site Wednesday, which she acknowledged in an Instagram photo of the prisoner barracks.

“My heart was heavy today,” she captioned the image.

“For ever let this place be a cry of despair and a warning to humanity, where the Nazi murdered about one and a half million men, women and children mainly Jews from various countries of Europe,” she wrote.

She ended the caption with a quote from Spanish-American writer George Santayana: “The one that does not remember history is bound to live through it again.”

The tribute to the memorial and museum came after Perry took the stage at the Kraków Arena in Poland on Tuesday as part of her Prismatic World Tour, with “Boom Clap” artist Charli XCX. Perry has also been documenting her European adventures with sillier photos of the Leaning Tower of Pisa, a selfie with the famed Italian sculpture David and some hanging puppets in Prague.

Her next stop? Vienna, Austria. The pop star has already acknowledged her Austrian arrival – she will perform there Thursday night – by posting a photo of the Arnold Schwarzenegger documentary Pumping Iron, which lightened the mood on her photo feed.

The singer wrote, “Nothing says welcome to Austria like a hot, young, cocky Arnold Schwarzenegger. Hello, VIENNA!”

This article originally appeared on PEOPLE.com