The Mormons had accumulated many possessions and had built beautiful brick homes, schools, and businesses in the seven years they lived and worked in Nauvoo. They could not take everything with them. With a hostile population in Hancock County and the surrounding communities, the Mormons had to leave as soon as they could manage it. The way was west, and west was the natural barrier of the mighty Mississippi River.

Beginning on February 4, 1846 the Mormons crossed the river by small wooden ferry, but that procedure was slow and cumbersome and it was winter. Meanwhile, the violence towards the Mormons was increasing unabated. Providently, the Mississippi River froze solid as a means of safe passage to the embattled Mormons. On February 16, 1846 the Mormon Exodus across the ice began in earnest. All "pioneers" left from Parley Street where there were wagons and people backed up for miles, awaiting their turn to cross the frozen river. Thousands of people, wagons, and tens of thousands of livestock all left behind the beautiful city they had built. The Exodus of the Latter-Day Saints from their beloved Nauvoo stands as the largest forced migration in American history.

In 1848 an arsonist set fire to the beautiful Nauvoo Temple. Three years later, what had been left standing was hit by a tornado and virtually destroyed. The stones were used by others to build homes and offices of their own. Of the ornate 2.5 ton decorative caps from the pillars of the temple, called "Sunstones,"only two of the original 30 are known to still exist. One is in the Smithsonian Institute (there since 1989) and the other is on the original site of the Nauvoo Temple. Encased in a protective housing to guard against rain and sun, the single Sunstone is a solemn reminder of the power of faith and the spirit of the Mormons.