Most people don't think much about their pen refills. These bits of plastic usually end up in the garbage, inevitably adding to the world's waste problem. Artist Sreenivasulu M.R., however, has found a beautiful way to repurpose the oft-forgotten ink holders—by using them as the raw material for architectural works of art.

The artist began collecting the pen refills as part of his campaign, "Say No to Plastic." Friends and relatives would donate their old pens instead of throwing them away, and these would-be pieces of trash went on to help create models of landmarks like Big Ben, the Eiffel Tower, and the Tower of Pisa. His Taj Mahal replica is comprised of over 700 pen refills and made it into the India Book of Records in 2012.

Check out the incredible creations in the video below.