From Jericho, one could hear the sound of the wake up call. From Jericho, one could hear the sound of the wood that Bet Katin made for the sink. From Jericho, one could hear the sound of the Shofar. And some say even the sound of the Kohen Gadol when he would say Hashem's Name on Yom Kippur. From Jericho, one could smell the scent of the Ketoret.
All firsts are to be consecrated.
The first fruits would be brought to the Beit HaMikdash to be given to the Kohen . First born animals are automatically designated as sacrificial animals. The first city in Eretz Yisrael that G-d handed to the Jewish People was no exception. When Jericho was conquered, it was sanctified and declared forever forbidden to rebuild, in order that the the miraculous fall of the Walls of Jericho should be apparent. The site of the Beit HaMikdash , however was destined to be in Jerusalem on Mount Moriah.