Calum Ramm has a thing for running shoes.
Although he goes through about a pair a month, he doesn't like to throw them out.
"I have so many miles on them. I'm like 'That pair has 600 miles,'" the Crownsville resident said.
After he runs seven marathons — one on each continent — in seven days in January, he will have a pair recording the 183 miles of the World Marathon Challenge.
Ramm, a 2011 Naval Academy graduate, will be one of 12 people running in the challenge, which is in its second year.
"I've been training for this my whole life," said Ramm, a 26-year-old Marine Corps captain stationed at Fort George G.