The full cruise, which will launch in January 2021, will be a long one, exceeding all but a few luxury cruises that have been created in recent years. It is scheduled to last 167 days, make 107 port calls and visit 30 countries. The only continent it won't touch is North America.

"Silversea's upcoming world expedition is like nothing we've ever seen before," said Ashton Palmer, president of ExpeditionTrips, an agency in Seattle that specializes in the expedition market.

Read More