Final answer:
The detail from 'Gilgamesh: A New English Version' that best illustrates a courageous hero is when Gilgamesh goes in search of immortality despite the likelihood of failure.
Step-by-step explanation:
The detail from Gilgamesh: A New English Version that best illustrates a courageous hero is the moment when Gilgamesh goes in search of immortality even though he knows that it is unlikely to be successful. This demonstrates his bravery and determination to overcome death and achieve greatness. Despite the risks and obstacles he faces, Gilgamesh shows courage by facing them head-on and not giving up.