Sometimes a race is not enough. Sometimes a runner just wants to go further. Thats what happened to Dennis Martin and Brooke Curran. Martin, 46 , a retired detective from New York City, took up running after his first wife died. Curran, 46, a philanthropist(慈善家)from Alexandria, started running to get out of the house and collect her thoughts. Both she and Martin got good at running but felt the desire to do more. 'The more I trained, the better I got,' Curran said, ' but I would cross the finish line with no sense of accomplishment. ' Eventually, they worked up to running marathons(马拉松)(and longer races)in other countries, on other continents. Now both have achieved a notable-and increasingly less rare milestone: running the 26. 2-mile race on all seven continents. They are part of a phenomenon that has grown out of the running culture in the past two decades, at the intersection of athleticism and leisure: ' runcations,' which combine distance running with travel to exotic places. These trips, as expensive as they are physically challenging, are a growing and competitive market in the travel industry. ' In the beginning, running was enough,' said Steen Albrechtsen, a press manager. ' The classic marathon was the ultimate goal, then came the super marathons, like London and New York. But when 90, 000 people a year can take that challenge, it is no longer exciting and adventurous. Hence, the search for new adventures began. ' 'No one could ever have imagined that running would become the lifestyle. activity that it is today,' said Thorn Gilligan, founder and president of Boston-based Marathon Tours and Travel. Gilligan, who has been in business since 1979, is partly responsible for the seven-continent phenomenon. It started with a casual talk to an interviewer about his company offering trips to very continent except Antarctica. And then in 1995, Marathon Tours hosted its first Antarctica Marathon on King George Island, off the tip of the Antarctic Peninsula: 160 runners got to the starting line of a dirt-and ice-trail route via a Russian icebreaker through the Drake Passage. At the beginning, Martin took up running just to______.