Building walls was a recurrent theme in the presidential race. For cities, walls do much more than protect borders. Of course they can divide us, the way medieval ramparts helped to repel invaders. But they also can bring us together.

Seating walls provide places of gathering and conversation. Even retaining walls, which shore up steep slopes, are celebrated for climbing. And memorial walls and columbaria are designed to be places of gathering, albeit sacred and often somber ones. Here is a small sampling of some of the walls of the Twin Cities and what they provide in our urban landscape.

For thousands of years, the Mississippi River swelled and shrank and shifted course. In Minneapolis, we see traces of the river’s changing course in the steep slopes of Lowry Hill, the Oak Grove neighborhood south of Loring Park and in Bryn Mawr.

It’s no surprise that many of Minneapolis’ most impressive retaining walls are found in the Lowry Hill neighborhood near the Walker Art Center. Because these stretches of what had been river bluff promised dramatic vistas, they were desirable sites for 19th-century builders, who constructed retaining walls, including the gray limestone wall that wraps the corner of Groveland Terrace and Dupont Avenue S. Gently sloping inward and topped with stepped caps, the wall sweeps up Dupont with gentle curves. On Groveland, it runs beneath a canopy of old yew trees, arcing with the street and opening up new vistas as you walk.

The Platteville limestone used for this wall comes from a fossil-rich, ancient lake bed that appears in outcroppings along the Mississippi River. (You also can find Platteville stone in the Pillsbury “A” Mill and the Nicollet Island Inn. For early builders, it was plentiful and nearby.)

Preserving a historic hospital

In the late 1880s, Dr. Martha Ripley founded the Ripley Maternity Hospital, which served poor pregnant women in a time of high infant mortality. In 1896, the hospital moved to a five-acre parcel on Penn and Glenwood avenues N., overlooking Bassett Creek. In 1910, the former “Babies’ Bungalow” was built to isolate sick infants from other patients.

The location of the hospital campus, which forms the northern edge of the same former riverbank as Lowry Hill, required a retaining wall. A fieldstone wall was built along the sidewalk, stretching more than 100 feet. Perched above it, the Babies’ Bungalow was built with the same fieldstone.

Now known as Ripley Gardens, an affordable housing development, the old hospital campus is one of the city’s best examples of preserving a historic landscape and buildings as a coherent whole.

Behind Summit’s mansions

In St. Paul, the Mississippi River also shaped the city, carving a broad valley stretching over a mile from Summit Avenue to Cherokee Heights. Winding beneath Summit’s mansions, W. Irvine Avenue is a hidden trove of hillside architecture and solid walls of stone. Few visitors see the massive rough-cut limestone wall holding back the slope behind the palatial James J. Hill house. But you can experience the impressive scale of the wall by following the long stairs connecting Summit to the bike path below on the north side of Interstate 35E.

Just to the west, where Summit meets with Ramsey Street at the University Club, Summit Lookout Park sits atop one of the more impressive stone retaining walls in Minnesota. In the 1850s, the site was home to Carpenter’s Hotel, which offered dramatic river views from its rooftop observation deck. After the hotel burned in 1887, city park commissioners bought the site and built a massive limestone retaining wall topped with an ornamental iron railing. Both the wall and railing endure as testimonies to early planning and investment in the parkway system.

Walls of memory

But what about a wall as monument? Probably the best known is the Memorial Wall at the Vietnam Veterans Memorial in Washington, D.C. Minneapolis also has a memorial, a columbarium for ash internment at Westminster Church. Designed by Coen + Partners, the textured copper screen separates the traffic of 12th Street from the narrow spaces alongside the church. Inside, set within the quietest part of the garden, a long limestone columbarium wall complements the church’s masonry. Westminster’s columbarium is best experienced by walking up the ramp from 12th Street and emerging to a view of downtown.

The recently replanted Mary Garden at the Basilica of St. Mary in Minneapolis continues a tradition from the Middle Ages, when artists portrayed Mary in a walled garden filled with flowers.

The Mary Garden includes flowers, fountains and a statue of Mary. It’s the wall framing the space, however, that shelters it from the noise of nearby freeways and helps create an island of contemplation, an outdoor retreat, an opening to the divine. What could be more different from a border wall?

Frank Edgerton Martin is a landscape historian and Minneapolis-based design writer.