You see in what manner of fasting and prayer the saints will exercise themselves at that time. Observe, also, how hard the season and the times will be that are to come upon those in city and country alike. At that time they will be brought from the east even unto the west; and they will come up from the west even unto the east, and will weep greatly and wail vehemently. And when the day begins to dawn they will long for the night, in order that they may find rest from their labours; and when the night descends upon them, by reason of the continuous earthquakes and the tempests in the air, they will desire even to behold the light of the day, and will seek how they may hereafter meet a bitter death. At that time the whole earth will bewail the life of anguish, and the sea and air in like manner will bewail it; and the sun, too, will wail; and the wild beasts, together with the fowls, will wail; mountains and hills, and the trees of the plain, will wail on account of the race of man, because all have turned aside from the holy God, and obeyed the deceiver, and received the mark of that abominable one, the enemy of God, instead of the quickening cross of the Saviour.
Source: The End of the World (Pseudonymous) (New Advent)