Quantis armati caelum petiere Gigantes anguibus, aut quantus Lernae lassavit in undis Amphitryoniaden serpens, qualisque comantis auro servauit ramos… - Silius Italicus

...ceu tigride cerva
Hyrcana cum pressa tremit, vel territa pennas
colligit accipitrem cernens in nube columba,
aut dumis subit, albenti si sensit in aethra
librantem nisus aquilam, lepus.

Caeruleas Ticinus aquas et stagna uadoso
perspicuus seruat turbari nescia fundo
ac nitidum uiridi lente trahit amne liquorem.
uix credas labi: ripis tam mitis opacis
argutos inter uolucrum certamine cantus
somniferam ducit lucenti gurgite lympham.

The higher they climbed in their struggle to reach the top, the harder grew their toil. When one height had been mastered, a second opens and springs up before their aching sight.