1) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.

2) Male seahorses are the ones who give birth to their offspring.

3) The world's longest traffic jam occurred in China in 2010 and lasted for 12 days, stretching over 60 miles (97 km).

4) The Great Barrier Reef in Australia is the largest living structure on Earth and can be seen from space.