Hornets are the largest eusocial wasps; some species can reach up to 5.6 cm (2.2 in) in length.
The best known species is the European hornet (Vespa crabro), about 2–3.5 cm in length,
widely distributed throughout Europe, Russia, North America and Northeast Asia.

Whilst stings are painful - and can in some people cause anaphylactic shock - they are not as agressive as the common wasp and will normally avoid people.