Tonight and tomorrow is Tisha B'Av, the 9th of Av, the saddest of days in the Hebrew calendar, a day of fasting and mourning. Both the First Temple (833-423 B.C.E.) and the Second Temple (349 B.C.E.-69 C.E.) were destroyed on this date.
You can see how big and magnificent the Temple Mount was in the model below. Please click to enlarge the photo.

This famous model on a scale of 1:50 shows the Second Temple and the city of Jerusalem in the year 66 C.E. The Jewish Revolt against the Romans had not yet begun.
The model was recently moved from the former Holyland Hotel to the Israel Museum. The white dome at the top of the photo is the Shrine of the Book where the Dead Sea Scrolls are on view. The building on the far left is the Knesset.

More about the model here and here. A short and interesting summary of Tisha B'Av is here at the Chabad website. The Reform Jewish perspective can be found on the fine Velveteen Rabbi blog. Many other ideas about Tisha B'Av here, presented by the Orthodox Union.
I will post more tomorrow, God willing, here at Jerusalem Hills about tonight's reading of Lamentations. I myself do not fast on this day and am not in favor of building an actual Third Temple. I do observe the day in my own way.