BEIJING - When Li Caohua retired in her late 50s, the doctor immediately joined millions of other Chinese seniors and hit the road to see more of her giant country.

At the top of her destination list was tropical Hainan island in the south and the ancient villages around her home city of Beijing.

As she and hundreds of other seniors danced, played cards and chatted Thursday in the winding walkways of Beijing's Temple of Heaven, Li said it was her time to play.

"We are fortunate in China that we can travel, and I've seen so much," the 60-year-old woman said. "We're all traveling now to a lot of places."

Travel agencies and packages catering to elderly Chinese say business is booming, amid overall growth in the country's travel industry. The number of senior tourists in China jumped by 58 percent last year compared to 2013, according to the state-run China Daily newspaper, and 62 percent of Chinese senior citizens join organized tours.

There are many versions of senior-friendly trips designed for different income groups, with some low-cost options charging 3,000 yuan, or about $480, for five days on Hainan island, not including airfare, said Beijing travel agent Qi Chun Guan. 

"Before, the elderly saved all their money," Qi said. "Now, they want to go out and see the rest of the world. These people have seen their share of suffering in their lives. Now, with economic development, it's so different from previous generations."

The boom in travel has been one economic bright spot to a graying population that's presenting China with one of its most serious policy challenges.

With UN data showing the number of Chinese over age 65 projected to almost double to 210 million people by 2030, the country's retirement system will struggle to keep up, especially as China's one-child policy limits the number of working-age people who can pay for the pensions and benefits of their elders, said Yong Cai, an assistant sociology professor at the University of North Carolina, Chapel Hill.

"It's very clear that the next 10 to 15 years down the road will not be so good for the pension system," Yong said. "Xi Jinping has been saying China has to deal with the new economic reality and part of this is a new demographic reality."

For middle-class seniors, however, comes strength in numbers, Qi said. Elderly women known as "dancing grannies" fill the parks of many cities with their music and dance routines. Enormous groups of seniors are also regular sights at Chinese tourist attractions such as Beijing's Forbidden City.

Among the most popular domestic destinations for elderly Chinese are the southeastern coastal province of Fujian and southwestern Sichuan province, Qi said.

One 55-year-old property manager, who would only identify himself by his family name of Shu, said he took two-day trips to towns around Beijing with other older Chinese, paying 600 yuan, or about $100, for each excursion. On Thursday, he strolled along the Temple of Heaven's historic covered walkway, protected from the rain and taking in the fresh air, part of what he said was his semi-retired morning routine.

"If you have the money, you go out and play," Shu said. "I've learned to like it."