The phrase "monumental work" refers to a significant and important task or project that is of great scale or importance. It implies that the work is impressive, noteworthy, and requires a lot of effort and dedication to complete. Full definition
They created monumental works that sought to capture the natural beauty of the landscape. (saatchiart.com)
In terms of its emotional and intellectual impact, this a truly monumental work, and yet this is just a piece of paper pinned to the wall. (theguardian.com)
Rijksmuseum presents an exhibition of important monumental works by Henry Moore will open the Rijksmuseum's new gardens on 22 June 2013. (museumpublicity.com)