(CNN) — Since when were a bunch of kids so interested in ancient history?
Whole families were pressed up against the railings at Largo Argentina, the square in Rome, craning their heads toward ... a hole in the ground. Rome is full of holes in the ground, many of them historically significant, but this one was extra special. It contained the remains of the theater and temple where Julius Caesar was assassinated.
But the kids weren't there for the ancient general-turned-emperor, murdered by treacherous senators in 44 BC. They were there for the cats.
Here's more about Rome and four other places where cats have the run of the place:
1. Rome's kitty ruins
Rome's noble ruins are a favorite haunt of feral cats. The "gatti di Roma" star on postcards and wall calendars sold all over the city.
The ruins at Largo Argentina host an open-air cat sanctuary that's more than just a good show for visiting and local children. The city's strays have been fed and watered at the site almost since it was first excavated in the 1920s. The 1990s brought an injection of funds into the Torre Argentina Roman Cat Sanctuary, money that allowed more cats to be trapped, neutered and returned to their colony.
Now, thousands of sterilizations are carried out each year -- around 30,000 and counting since 2000.
2. Japan's cat islands
That's right: islands. Plural.
Tashirojima in Miyagi Prefecture, is the best-known feline isle in Japan. It usually goes by the name Cat Island.
Dogs have been barred from Tashirojima for as long as anyone can remember. The island's cats vastly outnumber its human population. Tashirojima's furry inhabitants are well cared for by local fishermen, who hope to ensure a good catch by leaving offerings at a cat shrine.
The island's most prominent structure, the Manga building and campsite, is embellished with a pair of pointy ears, in tribute to the island's lucky charms.
Japan's other cat island, Ainoshima, is a little more remote, a 20-minute ferry ride from Shingu port in Fukuoka.
A scrum of happy cats hangs out by the port, waiting for the next fishing boat or ferry to dock. In fact, the island represents a doubly incentive for the cats -- rugged Ainoshima is also a popular birdwatching site.
3. Houtong, Taiwan
The riverside town of Houtong, Taiwan, fell into feline celebrity by accident. Houtong once sat on top of Taiwan's largest coal mine. When the mine closed in the 1990s, the town's population dwindled. Then some new, furry residents arrived. The Houtong Coal Mine Ecological Park (Houtong Road, Ruifang District, New Taipei City; +886 2 2497 4143) was established to showcase the mining heritage of the town and surrounding hills. But visitors mostly come to photograph the 120 or so playful cats, who laze around the Cat Village and soak up the fuss -- and inevitable treats.
Houtong's proximity to Taipei -- it's an hour away by train -- ensures a steady stream of visitors each weekend. Cats here are used to amateur paparazzi. Their portraits are all over Facebook and Flickr.
4. Kalkan Kats, Turkey
A pretty resort on Turkey's Turquoise Coast, Kalkan is another tourist destination with an active cat protection squad. Established in 2008, KAPSA is a voluntary organization run by locals and expats that traps stray cats.
KAPSA neuters them and provides basic healthcare, then releases them.
Animal loving visitors regularly give up vacation time to help out and share their experiences and photos on the Friends of KAPSA Facebook group.
When tourists disappear for the winter, KAPSA feeds and cares for more than a thousand cats, relying on donations to fund its operations. Eager photographers can snap cats all over Kalkan, snoozing on hammam towels, curled up in fruit bowls or enjoying the air conditioning in the resort's stores.
Several often gather by the old mosque, close to Kalkan's beach, to pose for the cameras.
5. Hemingway's cats, Florida Keys
Ernest Hemingway earned a reputation as one of the world's great drinkers. There's even a statue of him propping up the bar in El Floridita, Havana. Less known is that Hemingway was also a cat lover.
In some rooms, it feels like the great author has just stepped out, even though he died in 1961. And his 1850s house is still a home -- to a colony of polydactyl, or six-toed, cats.
Hemingway was given a white six-toed cat named Snowball in the 1930s. Some of Snowball's descendents are among the 50 or so furry residents of the historic home today.