Construction workers laid down a giant “curb stone” at a downtown Boston hotel that is the largest in the world.
The massive structure was erected over a span of three days on Friday to commemorate the centenary of the US Civil War in Boston, a city which suffered huge losses from the Civil War.
The 1,800-tonne structure is made of “curtains of cement”, which have a hardness of about 1,000lbs (745kg).
It measures 18 metres (50 feet) high and is covered in white “corduroy” and green “pink stripes”.
It was built to commemorate Mass Ave in Boston where Union soldiers died during the Civil Wars.
It is the second largest concrete building in the US.
The construction workers are the first in Boston to lay down the massive concrete block in a major city, after a similar monument was erected in Boston in June.
Boston Mayor Marty Walsh, who attended the unveiling, said it was “an important moment” in the city’s history, as well as a “great day for Boston”.
The construction of the monument began in October.
The building will be covered in blue and red fabric, which is the colour of the city.
It will also feature a mural of the Boston Red Sox team and other iconic landmarks from the city of Boston, including the Boston Public Library and the Boston Common.
“Boston’s history is one of a rising tide of freedom and innovation that will continue to inspire generations to come,” Walsh said in a statement.