In the year 2448 from Creation (1313 BCE), Tammuz 16 was the 40th day following the Giving of the Torah at Mount Sinai, and the people of Israel wrongly expected Moses' return from the mountain (he would actually return on the following day). When their leader failed to return, they demanded from Aaron: "Make us a god that shall go before us". Hur (Moses' nephew, the son of Miriam and Caleb) tried to stop them and was killed by the mob. Aaron fashioned a calf of molten gold.
Links:
The Making of the Golden Calf (text of Exodus 32 with Rashi's commentary)
An anthology of Midrashim and Commentaries on the making of the Calf
The Day Before (on the deeper significance of Tammuz 16, from the teachings of the Lubavitcher Rebbe)
More on the Golden calf
See also "Today in Jewish History" for tomorrow, Tammuz 17.
Sometimes the cloud would be upon the Tabernacle for a number of days, and by G-d's command they encamped, and by G-d's command they journeyed.
And sometimes the cloud would be there from evening until morning, and the cloud was lifted in the morning and they journeyed...Or two days, or a year, or a month...By G-d's command they would encamp, and by G-d's command they journeyed. (Numbers 9:20-23.)
At every stop along their journey, whether it was for a year or for one day, the Children of Israel set up the Tabernacle and made all their offerings. Because they knew that they had been brought to this place by a divine hand, and so there must be purpose in this place, here, now.
Which teaches that in every journey of your life you must be where you are.
It may seem that you are only passing through on your way to somewhere else—but in truth there is purpose, divine purpose, in wherever you are right now.
Listen, learn, heal, plant seeds and water them. Neither you nor this place must stay the same.