To understand what the Bais Hamikdash (and in particular, the Second Bayis - with which we are here most interested) meant to our nation, we'll need a bit (but just a bit!) of background.
Jewish history is the story of a nation preparing; of a nation moving towards a goal. For our forefathers, the goal was the revelation at Mt. Sinai. Since then, we strive both as a nation and as individuals to reach perfection in Divine service. The Bais Hamikdash has historically played a giant role in this journey.
In each of its manifestations (whether as a tent-like Mishkan or a full blown marble, gold and cedar Temple), the Mikdash has served as the focal point of this national struggle. Perhaps our growth over the centuries was reflected in the changing appearance of the Mikdash itself. Perhaps, too, our failings were the cause, not only of the eventual destruction of the Temples, but of their falling fortunes.
The basic structure common to each Mikdash included a Kodesh Hakedoshim (Holy of Holies), covering the ark; a Kodesh (to the immediate east of the holy of holies) in which was placed the menorah, showbread-table and the small, golden mizbayach (altar); and an uncovered courtyard where the main mizbayach stood.
The Mishkan that Moshe Rebainu erected at the foot of Mt. Sinai was built to be taken apart and moved when needed. Dozens of times over the next decades, the curtains, columns and utensils of the Mishkan were carefully packed away and carried off into the desert behind the guiding pillar of smoke (or, by night, of fire).
Tent-like curtains covered the Mishkan, reflecting the temporary nature of our lives in those wilderness years.
After fourteen years in Eretz Yisroel, at a time when most of the country had been subdued for the Jewish settlers, a new Mishkan was built in Shilo with stone walls but the old curtain coverings for a roof....Our presence in Eretz Yisroel had become a little more permanent.
Shilo stood for 369 years. Upon its destruction, a more temporary Mishkan was erected, first in Nov, then in Givon.
Finally, after more than four centuries, Shlomo was allowed to build what was called Bais Olumim - eternal house. The Jewish people had come home. That bayis might well have remained a Bais Olumim, but for the sins of our fathers.
With its destruction 410 years after having been built, the greatest period in our history closed.
The Bayis built by Ezra and Nechemiya after seventy years of exile in Babylonia was a poor copy of the original. As much as it was refurbished and beautified over the years, the period of the Second Temple was a time of exile (note that Greek rule was called the "Greek exile" by our sages - despite the fact that the Bayis stood throughout).
Today, we await the building of the third Bayis - the real Bais Olumim.