They were taking selfies at the Anne Frank Memorial.
Feifer, a senior editor at Fast Company, immediately sent himself a one-sentence email he would read when he returned to New York.
"Inappropriate selfies," the email read.
Initially, he thought about just sharing this observation on Twitter, but decided showing, and not telling, might be a better idea. Taking to Twitter, Feifer searched for the words "selfie" and "holocaust" or "9-11 Memorial", "Chernobyl", "The Berlin Wall".
Thus began "Selfies at Serious Places", the tongue-in-cheek
Here's one from Pearl Harbor:
... at the Sept. 11 memorial:
... and the Holocaust Memorial:
It was a trend: people, mostly young adults, were taking selfies at all of these places.
"Some of them were totally respectful, and I didn't use those," Feifer said in an interview with Business Insider. He went on to explain how there were people who were taking photos of themselves clearly just to show they had been there.
"Those people would stand by signs or descriptive plaques and not smile."
But when it came to the many tasteless photos he saw where teenage girls were making the popular "kissy-face" (also known as "duck lips"), or young men throwing up the peace sign, Feifer gave no pause to putting those on the Tumblr. He even began to search "selfie" and "funeral", "car crash", "house fire", finding similar results each time.
When asked if he planned on continuing the Tumblr, Feifer said he didn't think so.
"I really like the form of the single-topic Tumblr because there's something powerful in seeing the visual repetition of an idea," Feifer explained. "But now the statement has been made, and it's a pretty obvious one."
What's the best filter for an incredible lack of self-awareness and respect?