PROMONTORY, Utah — Music, bells and cannon fire rang out Friday at a remote spot in the Utah desert where the final spikes of the Transcontinental Railroad were hammered 150 years ago, uniting a nation long separated by vast expanses of desert, mountains and forests and fresh off the Civil War.

An estimated 20,000 people swarmed to the celebration at Golden Spike National Historic Park northwest of Salt Lake City — the signature event of several days of festivities marking the railroad’s anniversary. Visitors came from as far as China, many decked out in old-fashioned dresses, top hats, bonnets and scarves.

The 1869 completion of the 1,800-mile rail line shortened cross-county travel from as long as six months in wagons and stagecoaches to about 10 days on the rails and served as a unifying moment for the nation. It became a pivotal moment in United States history that dramatically changed how people traveled and did business.

“It psychologically and symbolically bound the country,” said Brad Westwood, Utah’s senior public historian.

Interior Secretary David Bernhardt marveled at how engineering, courage and risk-taking came together to make it possible.

“The story of this site says so much about our country,” Bernhardt said at the event, which included a reenactment of an iconic “champagne toast” photo of railroad workers perched atop facing trains giving cheers to the epic feat. “The joining of the two rail lines created a new sense of connectedness that helped form a common national identity.”

The festivities featured many moments and remarks that highlighted the vital contribution of the Chinese workers who put in long hours in brutal conditions and haven’t always received their proper due throughout history.