Artist Nancy Holt’s best-known work, “Sun Tunnels,” is outdoors, huge and open to the public — but only a relatively small number of people have seen it in person. It sits on 40 acres she bought in a desolate part of the Great Basin Desert in northwest Utah, accessible only by dirt roads, with no buildings in sight.

It is made of four massive concrete tubes, each weighing 22 tons and towering more than nine feet tall. The tubes are precisely oriented to frame not only landscapes in the distance but also the ever-changing patterns of the sun and stars. By limiting what someone in a vast open space can see, Holt meant to make the universe more personal.

“Sun Tunnels was a way of bringing the universe back to human scale,” she said in a 2012 interview with the Telegraph newspaper in London. “It was a way of orienting one in space and time.”

Ms. Holt died Feb. 8 at Memorial Sloan Kettering Cancer Center in New York. She was 75. The cause was leukemia, her friend Carlotta Schoolman said.

As a young artist in New York’s West Village in the mid-1960s, Ms. Holt worked in far more common — and practical — media, including photography and poetry. But in 1968, she landed in Las Vegas for the first time, and it changed her life.

“We stepped off the plane into the vastness of the desert,” she said in an interview for “Nancy Holt: Sightlines,” a 2011 book for a traveling exhibition of her work. “I had an overwhelming experience of my inner landscape and the outer landscape being identical. It lasted for days. I couldn’t sleep.”

Joining her on that trip were kindred spirits in regard to using the landscape in art: her husband, Robert Smithson, and Michael Heizer, pioneers in the land art movement. Smithson’s seminal work is “Spiral Jetty” (1970), a 1,500-foot-long coil of black basalt rocks that stretches out into the Great Salt Lake.

In 1973, Ms. Holt was unloading cardboard tubes from her car to create a model of “Sun Tunnels” when she got the news that Smithson had been killed in a small-plane crash while surveying a site for a coming project. He was 35.

Ms. Holt took it upon herself to finish some of the works he had planned, starting with “Amarillo Ramp,” the piece he was working on in Texas.

“She spent a lot of her life looking after the legacy of her late husband’s career,” said Ben Tufnell, who curated an exhibit of Ms. Holt’s photographic and other works in London in 2012. “Often, she would put Bob’s work first, and I think that was at the expense of her own career.”

Another factor in Ms. Holt’s relative obscurity is that she seldom made art that could fit inside museums or galleries.

In 1974, she bought the Utah land for “Sun Tunnels” for $40 an acre. The concrete tubes were custom made according to her design, and she collaborated with a large team — including an astronomer, engineers, a crane operator, a helicopter pilot and on-the-ground workers — to install the 18-foot-long structures, laid out in a disjointed X configuration.

The formal opening was June 21, 1976, the summer solstice. The date was significant because during the twice-a-year solstices, a pair of tubes align directly with the sun at sunrise and sundown.

Nancy Holt was born April 5, 1938, in Worcester, Mass. She graduated from Tufts University in Medford, Mass., in 1960 with a bachelor’s degree in biology.

She moved to New York shortly after college and got involved in the arts scene. Many of her early works in land art, photography and videos included astronomical or scientific elements. She and Smithson married in 1963.

After “Sun Tunnels,” Ms. Holt received several commissions, including the design of Dark Star Park in Rosslyn, Va. She created large spheres of gunite, suggesting extinguished stars, to be placed in the park amid small water features and greenery.

Ms. Holt’s most ambitious work, “Up and Under,” was a winding, 630-foot-long earthwork in a former sand quarry in Finland. It included seven tunnels that people could walk through and opened to the public in 1998 after 10 years of development and construction.

She had no immediate survivors.

— Los Angeles Times