Featured photojournalist: Chip Somodevilla

Members of the United States Naval Academy freshman class do sit-ups as a team holding heavy logs Photograph: Chip Somodevilla/Getty Images

... an exhausting task for many Photograph: Chip Somodevilla/Getty Images

Freshmen push through tough physical exercises Photograph: Chip Somodevilla/Getty Images

Trainees help each other over the Dong Ha Bridge exercise Photograph: Chip Somodevilla/Getty Images

A freshman in a muddy ditch ditch as part of the "wet and sandy" exercise Photograph: Chip Somodevilla/Getty Images

Class members link arms and lay back in Maryland's Severn river as part of the same exercise Photograph: Chip Somodevilla/Getty Images

Wading out into the Severn Photograph: Chip Somodevilla/Getty Images

A pipe-patching challenge Photograph: Chip Somodevilla/Getty Images

A mock raid as part of the military operations/urban-terrain squad exercise Photograph: Chip Somodevilla/Getty Images

The mock raid continues Photograph: Chip Somodevilla/Getty Images

The class practise ground fighting techniques Photograph: Chip Somodevilla/Getty Images

... and class engage in a paintball battle Photograph: Chip Somodevilla/Getty Images

A freshman pours water out of her boot and eats a quick snack Photograph: Chip Somodevilla/Getty Images

Company 16 lead a two-mile run across the Naval Academy Bridge Photograph: Chip Somodevilla/Getty Images

Upperclassmen wear T-shirts quoting Winston Churchill as they instruct the freshmen Photograph: Chip Somodevilla/Getty Images