Chen Zuchang has a different way of documenting his travels - instead of taking pictures, he sketches the places he visits.

The 77-year-old retired engineer from Chongqing in Southwest China has drawn more than 100 pictures of the cities and countries he has visited since his retirement.

In 2015, together with his wife Luo Xiansui, also 77, Chen went on an 86-day around-the-world cruise, stopping off at 18 countries and regions in the Northern Hemisphere. The trip cost them 148,000 yuan ($21,600) each.

Then, starting in November last year, they took part in a 46-day cruise of the South Pacific, visiting 11 ports of call.

Before the trips, Chen researched the destinations they would visit and sketched drafts of the famous landmarks they planned to see.

"I made preparations for a whole year before the global tour," he said.

After visiting a place, while others were busy enjoying the ship's facilities, Chen would take to his cabin - armed with a full set of pens and drawing tools - to write his travel log and add more detail and color to his preliminary sketches.

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

At home, the couple live a simple life, hiking every day to keep their bodies fit.

Unlike many other Chinese seniors, who give their savings to their children, the retirees have decided to spend all their money on travel - a decision that their two daughters support.

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

Their voyages have not been without incident, however.

On their first cruise, the pair encountered a turbulent domestic situation upon reaching Cairo, Egypt.

"Our ship was supposed to stop at the port but there was gunfire in the city," Luo said. "All passengers were required to stay inside their cabins."

Instead of docking, the captain decided to change the destination and went on to anchor the ship in Marmaris, Turkey.

"Though we didn't plan to visit that port, it was absolutely stunning," Chen said. "I liked it very much."

In December, while cruising near the Solomon Islands, a 7.8 magnitude earthquake hit the region - a tsunami alert was issued, but no damage was done.

The couple have also borne witness to tragedy while out on their travels. On one cruise, a terminal cancer patient from Beijing joined them. He died after arriving in Tahiti, a tropical island in the southern Pacific Ocean, and was buried there by his family.

"What a wonderful ending," Luo said. "We would like that too."

This year, the pair plan to visit Antarctica and the Arctic.

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