Epochal

The fall of the Berlin Wall was really an epochal event.

Pope Francis has told the world's oil executives that a transition to less-polluting energy sources "is a challenge of epochal proportions."

When the first planets outside our Solar System were discovered recently, it was an epochal event.

But they were the great epochal design; their influence on locomotive development is felt to this day and their niche in railway history is secure.

It had been an epochal decade for cancer epidemiology, but equally, an epochal decade for tobacco.