On social media, some compared the fire to the images of New York's Twin Towers burning after two planes crashed into them in the September 11, 2001 terrorist attack. (Shutterstock/beboy)
"Very sad," "shocked:" these were the reactions of Americans to the fire at Paris's Notre-Dame Cathedral, an 850-year-old landmark whose destruction wiped out centuries of heritage.
"When I heard the news, it did strike me at a personal level," said Amy Sapenoff, 33, after attending a mass in the capital Washington.
The high school history teacher, a Catholic, explained she went on a walking pilgrimage last year from Notre-Dame to the Saint James the Great shrine in the cathedral of Santiago de Compostela, in northwestern Spain.
"I'm extremely grateful, because I was able to go, to see it and to go for mass," she added tearfully.
IT consultant Nicolas Nader, 48, said he was "heartbroken."
"My earliest memory of it is reading Victor Hugo novel about it," he added of the cathedral, which he described as a "Catholic treasure."
Outside Washington's National Shrine of the Immaculate Conception -- one of the 10 largest churches in the world -- Simon Ciccarillo, 24, said he could not "understand" the tragedy.
"I was very sad, I actually started kind of tear up a little bit," the Colombian-American, who works at the Department of Justice, told AFP.
'A symbol of Paris'
In New York, 90-year-old writer Judith Gutman recalled the "horror" of seeing Notre-Dame burning in images online.
"I was in Paris many, many times, I have seen Notre-Dame," she said near St Patrick's Cathedral in the heart of Manhattan.
"I am not religious, but as an icon, as a building, a structure that is a symbol of Paris, it is shocking."
For Matt Shrock, in New York on vacation with his wife and two children, it was "horrible" to see images of the tragedy.
"We were shocked, hoping that there was not something terrorist-related... it's unfortunately these days one of the first things that goes to your mind."
On social media, some compared the fire to the images of New York's Twin Towers burning after two planes crashed into them in the September 11, 2001 terrorist attack.
But the comparison was short-lived, since there were no victims in the Notre-Dame blaze and no link to terrorism has been established.
For Katie Conper, a student of Scottish history, pictures of Notre-Dame's iconic spire crumbling in the flames drew comparisons to the 1666 Great Fire of London.
"As a historian, it makes me very sad," said the 23-year-old, visiting from Toronto.
"As somebody who has never visited Paris before, it makes me even more sad, I always heard about Notre-Dame and I always thought about visiting this iconic landmark."
From the steps of St Patrick's Cathedral, whose doors opened in 1879, Cardinal Timothy Dolan -- the archbishop of New York -- said he prayed for the French cathedral and expressed the "sorry that we feel over the devastating fire at Notre-Dame cathedral in the heart of Paris."
"Indeed, the very heart of Europe and certainly the heart of civilization in so many ways," he added.
"I can only imagine... what it would do to us if a fire struck St Patrick's. We would all sense there's a fire in our home. That's what a cathedral really is."