Emptied milk cartoons are normally discarded and destined to our landfills. This act brings no good to the environment. However, this may not be the issue anymore because, 5,000 of the local elementary students in Spain were able to collect 50,000 boxes and built the Castle. This sustainable castle was hailed as the record holder in Guinness Books of Records. Designed by an architecture student, the eco-friendly tower has a length that measures 29 meters, width of 14.07 meters and height of 8 meters. In addition, the said tower were built using just glue and staples. With this eco-friendly art, landfills will be drastically minimized.