Ever spotted a honeycomb-like mound on the beach and wondered what it was? It's a reef built entirely by worms!

Risso’s dolphins are mysterious creatures usually only found in deep, offshore waters.

This seagrass species is a kind of flowering plant that lives beneath the sea, providing an important habitat for many rare and wonderful species.

Listen out for the 'chattering' song of the reed warbler, while wandering the UK's lowland wetlands in summer. A small, brown bird, they are quite hard to see.

The sea hare looks like a sea slug – but in fact has an internal shell. They can be up to 20cm long but are usually much shorter.

This tiny gamebird is rarely seen, but its distinctive "wet my lips" call can be heard ringing out over areas of farmland on summer evenings.