A major focus of the Yom Kippur service, is the Avodah, also known as the Temple service. We see how all of the holiness in Israel converge in one place on one day.
The holiest place on earth is Eretz Yisrael. The holiest city is Jerusalem. The holiest place in Jerusalem is the Beit Hamikdash. The holiest place in the Beit Hamikdash is the קדש קדשים, the Holy of Holies.
The holiest Jew was the Kohein Gadol. The holiest day of the year was Yom Kippur. All of these come together when the Kohein Gadol enters the Holy of Holies, only on this day.
Sadly, we have not been blessed to have lived to see the Kedusha of the Avodah on Yom Kippur. All we can do is read about it to get a glimpse of what it must have been like.
Thanks to the Temple Institute, their pictorial account of what went on helps us to visualize what took place. There is even a מחזור המקדש that has these pictures throughout the prayer service to help create a longing for the rebuilding of the third Temple.
Perhaps our longing for it, will help it happen more quickly. In the meantime, Yom Kippur is a good time to help us appreciate what it is that is so desperately needed to be a part of our lives.