The 74-foot-wide, 30-ton artwork was painted by Rivera before a live audience on Treasure Island during the Golden Gate International Exposition in 1940.
It's been on display at City College of San Francisco since 1961, and moving it took several years to plan.
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A truck with custom shock absorbers made seven trips to move the panels across town, driving five miles per hour.
Then a crane lifted the panels over power lines to put them in a ground floor gallery.
"We hope this amazing Rivera piece will beckon and compel people, who may not have visited our museum before, to step inside our doors," said Diana Nelson, SF MOMA's president.
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Visiting the mural is free.
You can see it at SF MOMA until 2023, when it will return to the City College of San Francisco.