People are vandalizing rock formations at US National Parks, and destroying unique geological features that have taken millennia to develop. Earlier this week, photographer Kevin Dunn shared a picture of graffiti on one of the spherical cannonball concretions at Theodore Roosevelt National Park in North Dakota, which is a particular hotspot for vandalism.
"This is on one of the 'cannonballs' at the Cannonball pull off," Dunn wrote, alongside a photo of a name and date scrawled on the rock using a permanent marker three years ago.
