Her husband, Dr. Lonnie Hammargren, built Big Bertha, a black 10-foot-tall model locomotive, in their backyard from a disparate collection of parts: a rail car believed to have brought Howard Hughes to Las Vegas, part of a road girder, a piece of an 1890 steam tractor, a boiler “from something entirely different, I can’t remember what,” Dr. Hammargren said. The wheels were from castoff parts of old CAT scan machine s.

“Oh, I just hate it,” Mrs. Hammargren said. “It’s awful to look at.”

That she wants Big Bertha gone is not surprising. What is astonishing is that Big Bertha is all that earns her wrath when nearly every inch of her vast home is overwhelmed by thousands of other bits of memorabilia, collections, bizarre shop projects and unadulterated junk.

The endless displays, which leave nary an inch of floor space inside or outside their home, in southeast Las Vegas, add up to a lifetime of acquisitions for Dr. Hammargren, a former two-term Nevada lieutenant governor and retired neurosurgeon.

Dr. Hammargren opened the home to the public on Sunday afternoon, as he does each year to observe the anniversary of Nevada statehood. Once a stately one-story house, it now has three floors and is attached to homes on each side that Dr. Hammargren bought over the years and loaded with his ever-multiplying collections.

The contents range wildly and appear to have little organization: a life-size doll of the late entertainer Sammy Davis Jr. sits as the conductor of a train that came from the Nevada Test Site nuclear proving ground. Dr. Hammargren is predominantly occupied by items from old Vegas casinos, scale models of famous sites from around the globe and various NASA space missions. Dr. Hammargren, 70, was a NASA flight surgeon who flew in jets with the likes of the astronaut Buzz Aldrin, a friend and occasional visitor.

The home goes by at least three names — the Castillo del Sol, the Hammargren Home of Nevada History and the Principality of Paradise. Dr. Hammargren calls his stead a country of its own and gives visitors faux gold coins with his face on them.

Trying to converse with Dr. Hammargren is a challenge because, like the disparate items crammed into his home, his soliloquies move without pause or logical transition from one world to another.

“My hobbies are astronomy and archeology, put it together that’s archostronomy, which is really the history of the world through stars, but oh, there’s the large pink egg that Liberace used to come out of every Easter during his Easter show,” he said. “And over there, that’s my Saddam Hussein-Osama bin Laden display, which I call the ‘Wacky Iraqi half tacky.’ ”

As a political figure, Dr. Hammargren, a Republican, was never taken all that seriously. His quirky persona helped him win election in 1990 and 1994 as the state’s lieutenant governor, an office with virtually no duty other than to ascend in the event of the governor’s death or removal.

But Dr. Hammargren did not seem to see the office that way. He startled the political establishment when, as acting governor when Gov. Bob Miller, a Democrat, was momentarily ou t of the state, he tried to appoint someone to fill a vacancy on the Lincoln County Commission. The secretary of state, also a Republican, refused to notarize the appointment. Dr. Hammargren ran for governor in 2000 but did not earn his party’s nomination.

He is well regarded as a physician. When he arrived in Nevada in 1971, he was one of only two neurosurgeons in the state and has operated on thousands of people since. Among his most notable patients was Roy Horn, of the illusionist duo Siegfried & Roy, who was attacked on stage by a tiger in 2003. Yet that, too, got Dr. Hammargren into some trouble when he disclosed to reporters details of the surgery.

On Sunday, as a crowd wended through the home, many took in the scenery with a mixture of bemusement, repulsion and, indeed, a little fear. “Oh God, what’s going to be in the next room?” asked Darren D’Amato, 44, of Henderson, who decided to visit after hearing a local radio host say on Friday that the open house was a rite of passage for Nevadans. “This place is a beautiful monstrosity. That’s the only way I can describe it.”

Mr. D’Amato wondered how the neighbors cope. Many grouse to the news media, anonymously, about the clutter and clatter and about concerns that such an eyesore damages home values in a subdivision of half-acre lots with neat lawns and tasteful facades. By contrast, the Principali ty of Paradise’s facade is a huge, homemade fiberglass replica of a Mayan temple.

The Hammargrens have skirmished with neighbors who have complained to local authorities, but the doctor has never been forced to limit or alter his home. Thousands come to see the place when it is open for visitors, but it has also topped local newspaper readers’ polls as the city’s biggest eyesore.

Yet Dotty Reeve, who weeded her yard across the street on Saturday, said she enjoyed her proximity.