Herculean task
US /hərˈkjuːliən tæsk/
UK /hərˈkjuːliən tæsk/

1.
impresa erculea, compito arduo
a task requiring tremendous effort, strength, or courage, often seemingly impossible to complete
:
•
Cleaning out the entire attic was a truly Herculean task.
Pulire l'intera soffitta è stata una vera impresa erculea.
•
Completing the marathon after only a month of training was a Herculean task for him.
Completare la maratona dopo solo un mese di allenamento è stata un'impresa erculea per lui.