Consider Ayat 18, Surat Muhammad.

In ayat 18 of Surta Muhammad of the Holy Qur'an, Allah Ta'ala says:--

"FAQAD JA'A ASHRAATUHA..... But some of its signs (of the Last Hour) have already come.."

When Mercy leaves hearts, people begin to kill, fight and destroy. Now we are in that era, everywhere people are fighting among themselves. A whip comes from Heaven with unexpected/terrible events like earthquakes, storms, floods and hurricanes. All of these are Signs of the Last Day... but majority of the people still do not go back to Allah Ta'ala. Instead, they say, 'It is Nature.' As long as they say this, 'Nature' will come against them every now and then.