Unprecedented levels of internal order are obtained in multiwalled carbon nanotubes grown by chemical vapor deposition with a nitrogen-doping level of 3%. The tubes are much more ordered than pure carbon equivalents, and are also externally straighter and thicker. The graphene layers are either pure zigzag or pure armchair with spacings close to that of graphite. hkl reflections indicate three-dimensional crystallographic register (see Figure and inside cover).