Excerpt from Mr. Adnan Oktar's Live Conversation on A9TV dated November 15th, 2013
Adnan Oktar: Our Prophet (saas) says that there is a treasure hidden underneath the Kaaba. That is something not known at all, who knows what will be discovered there. In the time of Hazrat Mahdi (pbuh), a search will be conducted underneath the Kaaba. We will find remains dating ten thousand, fifteen thousand, twenty thousand years back. We will find remains from those periods. We will see that even in those periods people believed in God and that there was belief in one God. These will be very important proofs. Our Prophet (saas) also foretells that Istanbul will be in the hands of Muslims, it is amazing that has infallibly been the case. In fact, just to prove this hadith wrong, they could have pressed and taken over Istanbul. But this is how it is in the destiny. It has to be in the hands of Muslims. Now, in the upcoming days another comet will appear. A very big, important comet will appear and that will also be a remarkable portent insha'Allah.