This week in 1923, the first U.S. President ever to visit Alaska drove the final spike into an Alaska Railroad track to signify its completion.

On a hot and sunny July 15 in North Nenana, President Warren G. Harding lifted a maul and struck a specially made golden spike into the rail at the northern end of the Mears Memorial Bridge. It was the last piece of track connecting the new Alaska Railroad between Seward and Fairbanks.

But there are a couple of mysteries surrounding President Harding and his trip north.

First, after Harding struck the $600 golden spike– after missing it twice– that valuable piece of history was replaced with an iron one to finish the track. The historically priceless golden spike, which would have a monetary value of more than $8,500 today, went missing.

The second mystery surrounds the death of Harding less than three weeks after that final spike ceremony. Harding and his entourage left Seward on board the USS Henderson on July 17. They made a brief stop in Cordova and then were greeted by residents of Sitka on July 23.

Two days out of Sitka, Harding began to experience severe abdominal pain after eating crab drenched in butter. Tainted shellfish was suspected, but no one else on the ship showed any symptoms of ptomaine poisoning. He continued to get iller as he traveled by train from Seattle to San Francisco, where he died on August 2 at the age of 57.

For years, a multitude of conspiracy theories surrounded his death.

Some people thought his wife had murdered him. Turns out he had a roving eye for the ladies that might make recent presidents look like choirboys.

Others speculated that members of his cabinet killed him to keep him from investigating their wrongdoings. And a few thought Harding may have committed suicide because he had learned his friends were crooks and he was weighed down by their bad deeds. Some people even thought Alaskans must have had a hand in the president’s death.

Recent investigations indicate that none of these theories were true. Harding had a history of heart problems due to his unhealthy diet and fun-loving lifestyle. His medical records show he suffered from high blood pressure and an enlarged heart. A heart attack caused his death, so the mystery of his death was solved.

But the mystery of the golden spike remains.

For years people thought it was at the Harding Museum in Ohio or the Smithsonian in Washington, D.C. But, museum representatives at those locations say it is not in their collections. The golden spike still is missing.