This pictures speaks for itself.

The Mydas fly (Gauromydas heros) is the world's largest fly. It can reach body lengths of 2.8 inches (7 centimeters) and a wingspan of 4 inches (10 centimeters). Mydas fly are found in arid and semiarid regions of the world, but are infrequently encountered as the adult lifespan can be quite short.

The Leatherback Sea Turtle is the largest turtle in the world, weighing approximately 900 kg. Contrary to appearance, the leatherback doesn't actually have a shell. What looks like a shell is in fact a leathery skin supported by small bones. This gives it a flexibility that a solid shell would not provide, allowing it to dive to astonishing depths.

Aside from claiming the title of the largest animal known to have ever lived, the blue whale (Balaenoptera musculus) possesses a heart big enough to house a human. The heart of an average sized blue whale weighs 180 kg (400 lb) and is also the largest known in any animal.

During the first seven months of its life, a blue whale calf drinks approximately 380 litres (100 US gal) of milk every day. Blue whale calves gain weight quickly, as much as 90 kilograms (200 lb) every 24 hours. Even at birth, they weigh up to 2,700 kilograms (6,000 lb) - the same as a fully grown hippopotamus.

Blue whales have proportionally small brains, only about 6.92 kilograms (15.26 lb), about 0.007% of its body weight, although with a highly convoluted cerebral cor ...

The blue whale is not only the largest animal alive currently, but is likely the largest animal ever to have lived.

Depending on the location, blue whales can grow to be 33 meters (108 feet) and weigh as much as 181 metric tons (200 imperial tons).They can live to be 90 years old and ingest about 3.6 metric tons (4 imperial tons) of krill each day. Blue whale are considered endangered by the IUCN.

This is the Giant weta. Native to the small islands of New Zealand, it's one of the heaviest insects in the world - the largest on record weighed around 70 g.