According to Official Guinness Records,
The world's largest carbon nanotube model contained 65,000 carbon atoms and measured 360 m (1,181 ft) long. It was constructed on 22 April 2005, using Molecular Visions chemistry building blocks, by students and staff at Rice University's Center for Nanoscale Science and Technology, Houston, Texas, USA.
For a complete list of 2005 records, please visit 2005 Guinness Records in United States.