Shanghai by Chen Zuchang. [Photo provided to China Daily]

He brought along a whole set of drawing pens and tools on board. After visiting each place, while others enjoyed the facilities and activities, Chen would work in his cabin, writing a travel log, and adding colors and more details to his drafts.

"At first, my husband felt reluctant to travel and I encouraged him to see more and learn more," Zhao said. "Now he can use his skills to make our trip more meaningful."

The retirees live a simple life and climb mountains every day to keep fit. Unlike other Chinese seniors who usually leave the savings to their children, the couple spends all their money on travel.

They have two daughters who are very supportive of their parents' lifestyles.

"We have nothing to worry about and we prepare for everything that would happen on the road," Luo said.

This year, they plan to reach the two poles: Antarctic and the Arctic.