We started in the small, immigrant-packed city of Hamtramck, Mich., and ended up in the woods of Canterbury, N.H., where we attended an unusual Christian service. Over the course of our trip, we met many people intent on preserving and spreading traditions of all kinds.

Hamtramck, Mich.

In Hamtramck, Mich., a tiny city enveloped by the state’s largest, more than 30 languages are spoken. It is, in many ways, a microcosm of America — a place where people from all over seem to fit.

On a Friday in August, a Yemeni man wearing a traditional white dress, with a dagger tucked into his belt (it’s just an accessory), runs through the city’s main thoroughfare on his way to a summer wedding. As he passes by, a motorcycle gang pulls up to the local bar, parking their bikes in a tidy row. In the distance, Ukrainian church bells ring.

Across the street from a towering statue of Pope John Paul II, a Bengali couple purchases a new bed from a furniture store. For the last 100 years, this place — sometimes called “the world in two square miles” — has been an introduction to this country for immigrants and refugees from all over.

Inside a convenience store in Hamtramck.

The doner kebab at Balkan House.

A relatively new arrival is Balkan House. The owner, Juma Ekic, was born into a Muslim family in Bosnia in 1980. When she was 12, she fled with her family to Germany to escape the Bosnian Genocide. The Ekics resettled in the small town of Glan-Münchweiler. Trips to the doner kebab shops, which were growing in number with the population of Turkish immigrants, became a source of comfort for her and her nephew, Dennis. Their stay was brief. In 1996, the German government ordered an expulsion of the country’s 320,000 Bosnian refugees; in 1999, the Ekics left for Hamtramck, which was absorbing refugees and immigrants from the Eastern Bloc. With them came the notion to open up a kebab shop of their own. “It was the closest thing to our childhood,” Mr. Ekic, 28, says. “You never lose that taste.” The restaurant opened in March. “This is a starting point for all immigrants. There’s a piece of everybody left here,” Ms. Ekic says, speaking of the city broadly, “and we want this to be a starting point for somebody too.”

Muad Nouman sits to eat a late-night shawarma wrap at Boostan Cafe in Hamtramck after a game of soccer. Originally from Yemen, he’s been living in Hamtramck since the ’90s. He went to Hamtramck High School. He loves it here. But his family, his wife, some of his kids (he has six) are back in Yemen, where a civil war rages on.

Detroit, Mich.

The Central Congregational Church was established in 1953 on Detroit’s west side by the Rev. Albert Cleage Jr. His idea was to build a church that spoke directly to African Americans, with sermons that preached self-determination and black separatism: “A nation within a nation,” as he put it.

Bishop Mbiyu Chui, who leads the Shrine of the Black Madonna. His church was the birthplace of the Black Christian Nationalist Movement, and has retained some of that group’s ideologies.

In 1967, the church was renamed the Shrine of the Black Madonna, and became the bedrock of the Black Christian Nationalist Movement in the United States. Its members were a political and social force in Detroit; they helped elect the city’s first black mayor, Coleman Young, and challenged the dominant white Christian narrative. At the altar, a painting depicts the Madonna as a black woman.

Bishop Mbiyu Chui, who joined the congregation in 1971, says the mission was for parishioners to defend “their right to human decency, to create a better community than the one we inherited.” It’s an idea that, for him, extends far beyond these walls, or the city limits.

“My hope is that it’s not too late for the majority of the country to take back what’s rightfully theirs — ours: the political process,” he says. “The democratic process is supposed to be by the people, for the people, so we need to make that happen again.”

Inside the Alfonso Wells Memorial Playground stands Detroit’s Eight Mile Wall — a stark, physical reminder of the history of segregation in this city and its reverberations. It was built in 1941 to separate a white neighborhood from a black one.

“The same idea that propelled this wall, is the same idea that is propelling his idea of a wall.”

Jamon Jordan leads a tour at the Eight Mile Wall.

Jamon Jordan, 48, is the founder of the Black Scroll Network, a tour company focused on the social, political and cultural history of African Americans in Detroit. The Eight Mile Wall is a stop on many of his tours. Mr. Jordan sees it as both an artifact and a contemporary symbol.

“Even the whole idea of walls has become a new thing because the political leader in the country is talking about walls,” he says, referring to President Trump’s campaign promise of a wall along the U.S.-Mexico border. “The wall is meant to divide, it’s meant to dehumanize a certain group of people, it’s meant to say that they’re less than, and you’re more than.”

The homecoming festival in Dearborn, Mich.