Facilis decensus
Averni;
Noctes atque dies patet atri ianua
Ditis.
Sed gradum revocare superasque evadere ad auras;
Hic opus, hoc labor, est.
The descent to
Hell is easy.
The doors of
Hades' hall stand open
night and day.
But to retrace your steps and climb out to the skies above -
Here is the task, and this is the labour.
Vergil,
Aeneid,
Book 6