They are one of the old species on Earth. Judging from fossils tortoises have roamed our planet for more than 200 million years. There's evidence of turtles, which live in water, dating back 150 million years. So they're a tad "younger."

Turtles and tortoises have withstood natural catastrophes and even the ice age. Adult turtles harbor no enemies - apart from humans. We're their biggest threat. Tortoises were once a popular dish among sailors. Some turtles are still considered a gourmet dish. And when we're not eating them, we steal or destroy their habitats.

This is "Lonesome George" - not as he lives and breathes, but embalmed in a museum. The giant tortoise died in 2012 due to heart failure. Lonesome George was thought to be the last of his kind. He was discovered in 1971 on the Galápagos Islands off Ecuador. Researchers have since found 17 related turtles.

Lonesome George grew to be about 100 years old and weighed 90 kilograms. That was nothing compared to Esmeralda here: she's thought to be the oldest living tortoise. Esmeralda lives on Bird Island in the Seychelles. She weighs over 400 kilograms and could be as old as 200 years. Well, it's all rumors about her age, but she's definitely old.

This is "Timothy the Tortoise," a tortoise with a wild life. Timothy was born in around 1844. In 1854, Captain John Courtenay Everard found Timothy on a Portuguese pirate's ship. After that, she was carried as a mascot on numerous warships until she retired in 1892. Timothy lived in the rose garden at Powderham Castle until her death in 2004. Despite her name, Timothy was female.

This is a terrapin, a European bog or swamp turtle. They are not as old as the examples so far, but they are a unique specimen that can be found in the wild in Central Europe. Terrapins are listed as endangered in Germany, Austria and Switzerland. In 2015, it was named Germany's reptile of the year.

The giant tortoises of the Galápagos Islands and the Seychelles can appear huge at over one meter in length. But ocean-bound turtles are even bigger. This leatherback turtle is 2.5 meters long and weighs 900 kilograms. Male speckled Cape tortoises (also known as the speckled padloper tortoise) is the smallest at just 8 centimeters in length.

But don't be misled to believe the leatherback turtle is slow just because of its size. It can, if necessary, hit speeds of 35 kilometers per hour. Newborn turtle babies are also fast. Bringing up the rear, though, are Gopher tortoises. They live on land and move at a comfortable 0.21 to 0.48 kilometers per hour.

So we now know turtles are a hardy lot. But are they tough enough to deal with humans? Colin Limpus, an oceanographer based in Australia, says it all depends on the challenges we throw at them - and how much we help them. It's something to think about - not just on World Turtle Day.