  Cylindrical multishell structure is one of the prevalent atomic arrangements
in nanowires. Being multishell, the well-defined atomic periodicity is hardly
realized in it because the periodic units of individual shells therein
generally do not match except for very few cases, posing a challenge to
understand its physical properties. Here we show that moir\'e patterns
generated by superimposing atomic lattices of individual shells are decisive in
determining its electronic structures. Double- walled carbon nanotubes, as an
example, are shown to have spectacular variations in their electronic
properties from metallic to semiconducting and further to insulating states
depending on their moir\'e patterns, even when they are composed of only
semiconducting nanotubes with almost similar energy gaps and diameters. Thus,
aperiodic multishell nanowires can be classified into new one-dimensional
moir\'e crystals with distinct electronic structures.
