Ben Lascelles / Prostrator about to perform body-length prostrations over the entire length of the circumambulation around Mount Kailash. The pilgrim bends down, kneels, prostrates full-length, makes a mark with his...

Ben Lascelles / Prostrator about to perform body-length prostrations over the entire length of the circumambulation around Mount Kailash. The pilgrim bends down, kneels, prostrates full-length, makes a mark with his...

Ben Lascelles / Prostrator about to perform body-length prostrations over the entire length of the circumambulation around Mount Kailash. The pilgrim bends down, kneels, prostrates full-length, makes a mark with his...

Ben Lascelles / Prostrator about to perform body-length prostrations over the entire length of the circumambulation around Mount Kailash. The pilgrim bends down, kneels, prostrates full-length, makes a mark with his...

Tony Phelps / Bontebok (Damaliscus pygargus pygargus) males down on their knees, sparring, DeHoop Nature reserve, Western Cape, South Africa, August

Charlie Summers / White-bearded Gnu / Wildebeest (Connochaetes taurinus) in a dominance fight on their knees with dust flying. Ngorongoro Crater, Tanzania.

Michel Poinsignon / Bald cypress knees (Taxodium distichum) Courant d'Huchet Landes, France, August.

Michel Poinsignon / Bald cypress knees (Taxodium distichum) Courant d'Huchet Landes, France, August.

Michel Poinsignon / Bald cypress tree (Taxodium distichum) and knees, Courant d'Huchet, Landes, France, August.

Michel Poinsignon / Bald cypress tree (Taxodium distichum) and knees next to river, Courant d'Huchet, Landes, France, August.

Petra Wegner / Woman sitting holding tissues s with Cavalier King Charles Spaniel, ruby, male with paws on her knees Model released

Jeff Rotman / El Molo child suffering from rickets, caused by a diet consisting primarily of fish. El Molo children suffer from vitamin D deficiency, which develops into the nutritional disease causing deformities...