Just how big is the boom in river cruising? So big that the head of North America’s largest river line is openly talking about having 100 ships on the world’s rivers by the end of the decade.

“We shouldn’t disregard the possibility,” says Torstein Hagen, chairman of Viking River Cruises, which currently operates 35 vessels from Europe to Southeast Asia.

Speaking with cruise writers this week during inaugural festivities for his line’s newest ships, Hagen said he saw no end in sight to the soaring demand for river cruises that has characterized the past decade.

Photo Credit: A Viking River Cruise ship is docked in Koblenz, Germany. Viking River Cruise / Flickr