The last of the Elders (z'keinim) who were contemporaries of Joshua and outlived him, passed away in the year 2533 after creation. They were part of the chain of Torah transmission as listed at the beginning of Ethics of the Fathers: "Moses received the Torah from Sinai and gave it over to Joshua. Joshua gave it over to the Elders, the Elders to the Prophets..."
In ancient times, this day was marked as a fast day.
[Some are of the opinion that this occurred on the 5th of Shevat].
Chabad-Lubavitch Chassidim observe the special customs of the Shabbat prior to the yahrtzeit (anniversary of the passing) of the sixth Lubavitcher Rebbe, Rabbi Yosef Yitzchak Schneersohn (1880-1950), which occurs next week, on the 10th of Shevat.
Link: A Letter from the Lubavitcher Rebbe outlining his suggested observances for the Shabbat preceding Rabbi Yosef Yitzchak's yahrtzeit.
In Torah, we mirror on earth that which G‑d performs on every plane of reality.
If so, since the Torah prohibits dislocating even a single stone of the Holy Temple in Jerusalem, how could it be that G‑d brought the entire structure to ruins?
For it would certainly be absurd to imagine that the Assyrians or the Romans had the power to set fire to G-d’s house.
It must be that this was not an act of destruction. Rather, it was the initial phase of a much greater construction, one that would be eternally indestructible.
And for that to occur, the Temple had to be temporarily leveled to its foundations and G-d’s people had to be scattered to the furthest reaches of human habitation.
Why? Because as long as there is any place in this world that considers itself outside the realm of holiness, there remains a place for the destruction of G‑d’s Temple.
But in our exile, we meet face to face all that considers itself foreign to the divine. We grasp its reins, extract its poison, and channel its power.
This third and ultimate Temple, then, will be built of the outside turned inward, of darkness taught to shine, of the other converted to the One, of the most sinister enemy transformed to a faithful ally.
No opposition will remain in the universe. And so it will last forever.
Then we will see that in truth, there was never any destruction. There was only rebuilding, growth, and eternal, deep love.