While the house has a ticket back to America, the question of where it would find a permanent home remains unanswered.
The hurdles seem huge, the logistics daunting, but calls and emails have gone out for help to institutions including Brown University in Rhode Island, the Museum of Modern Art in New York, the Charles H. Wright Museum of African American History in Detroit and the Brooklyn Museum, among others, Mr. Mendoza said.
At least two institutions — Brown and Wright — said they were seriously considering the project.
“The house has a symbolic importance — it’s important in the narrative of her life,” said James Nash, a board member and the driving force behind the foundation’s pledge. “She suffered for a huge act of courage. It should be here, not in Berlin.”
Mr. Mendoza, who lives in Germany with his wife, Fabia, a fellow artist and filmmaker, and their young son, said it’s important now more than ever to repatriate the house to the United States, a nation convulsing from deep racial and social wounds.
“I’ve been out of the U.S. for 25 years, and I’m looking at it through a telescope,” he said. “I’m seeing a dark time in our history.”
Mr. Mendoza points to the deadly violence that engulfed Charlottesville, Va., when neo-Nazis and far-right marchers clashed with counterprotesters. That the rally began over the push to remove some of the nearly 1,500 Confederate monuments in the country speaks to his quest, Mr. Mendoza said.
He said the house would be a necessary addition to the comparatively sparse number of monuments dedicated to the civil rights movement. Mr. Mendoza envisions a temporary exhibition at first. To him, the house is a totem of tolerance, embodying the woman who “changed the world” by saying no.
In 1955, Ms. Parks refused to give up her bus seat to a white person in Montgomery, Ala., sparking a seminal bus boycott. After she received death threats, Ms. Parks sought the safety of her brother’s house at 2672 South Deacon Street in 1957.
She arrived “homeless and penniless,” her niece Rhea McCauley, who is nearly 70, recalled. “She literally started her life over when she came to the city of Detroit. She was blacklisted.”
The three-bedroom house cocooned a whopping 17 people at the time, Ms. McCauley said by phone from Detroit. Her aunt stayed there for two years, finding some measure of peace. Ms. Parks died in 2005, at age 92, in Detroit.
By then, the house had long been lost to foreclosure. After the financial crisis of 2008, Ms. McCauley snatched it off the demolition list for $500. When she met Mr. Mendoza through mutual acquaintances and he expressed interest in shipping the house abroad, she embraced the plan.
“He took the house where he needed to take the house to preserve it,” she said.
Since then, people like the German vice chancellor, Sigmar Gabriel, and the boxing champion George Foreman have made pilgrimages to see it. Ordinary Germans, too, have visited, pleased with the idea that their country is host to a symbol of the American civil rights era.
Now, Mr. Mendoza is looking to America to reclaim the house.
The linchpin of the plan fell into place once the Nash foundation pledged about $45,000 for the trip back home. Mr. Nash said he had learned of the house’s odyssey in an article by The New York Times and emailed Mr. Mendoza in June to ask how he could help.
“Rosa Parks has always been a hero to me,” he said by phone. “And as I learned more about this, my admiration and respect has gown.”
But where should the house spend its third life?
“Should this house go on the lawn of the White House for all time?” Mr. Mendoza asked. “Yes, why don’t we start with the house that was built by the slaves of this country.”
Mr. Nash, a former professor of moral theology at the Catholic University of America in Washington, is partial to relocating it to the capital, where he lives. “My dream is to have it at the new African-American museum in D.C.,” he said.
Easier said than curated. Linda St. Thomas, chief spokeswoman for the Smithsonian Institution, of which the National Museum of African American History and Culture is a part, said by phone that Ms. Parks was already “well represented” at the Washington museum and that it was unlikely the institution would host the house.
Jo-Ann Conklin, director of the David Winton Bell Gallery at Brown University, said the project “could be extraordinary — but it’s a big project and the gallery is booked two years in advance.”
But the Parks home has caught the eye of the Center for the Study of Slavery and Justice at Brown. Anthony Bogues, the center’s director, said by email on Friday, “The house is of enormous symbolic importance — particularly in these times.”
An exhibition may be possible, but there are still details to discuss. “From the C.S.S.J. perspective,” said Dr. Bogues, a professor of humanities and critical theory, “this is an important conversation, since we are committed to a public history program about the history of racial slavery and its legacies.”
But in Germany, Nikolaus Bernau, an art and architectural critic and historian, has a different idea. He wrote an editorial in the daily Berliner Zeitung in April arguing that it should be placed in the Humboldt Forum, a huge cultural and museum project in the heart of Berlin.
“For America, it has no relevance,” he said in an interview. “It’s very clear, because nobody was interested in taking the house — even the National Museum of African American History and Culture.”
The house should remain in Europe, Mr. Bernau said, because it would be “one of the only connections Berlin and Europe would have to Rosa Parks.”
But Juanita Moore, president and chief executive of the Wright Museum, is adamant. The house belongs in Detroit.
“Rosa Parks is really held in high esteem here,” she said. “The house represents her life in Detroit. As an actual artifact, it lends itself to the larger conversation about what we’re dealing with racism in this country today.”
When Mr. Mendoza made overtures about finding the house a home, Ms. Moore said on Friday, the museum was “enthusiastic.” She added, “We absolutely are discussing it with him.”
When the artist visits the country this year for a speaking engagement, she said, the museum will discuss “his broader vision.”
Douglas G. Brinkley, who wrote a biography of Ms. Parks and is a professor of history at Rice University, said, “The Rosa Parks Detroit home could be used on campuses as a springboard to have a conversation about who Rosa Parks was and why she matters.”
“For kids to be able to touch some of the wood of the Rosa Parks house can be an interesting way to advance the cause of history.”
For now, the house sits in Mr. Mendoza’s garden like a portal to another time. White paint stains the bottom part; the top is black. He is working on the interior.
“We have the original floors that she would have walked on,” he said proudly. “We have the original doors, the stairs that she would have walked up.”
“I’ve been put in the position of taking care of a national monument,” he added. “I believe it should be put behind bulletproof glass.”