  It is well-known that traversable wormhole solutions to the Einstein
equations require the existence of an exotic matter source violating the null
energy condition. An apparent exception is the overcharged Kerr-Newman-NUT
solution of the Einstein-Maxwell equations, which has all the properties of a
geodesically complete, traversable wormhole spacetime. We show that the exotic
matter sourcing this consists in two counter-rotating tensionless straight
cosmic strings -- the Misner-Dirac strings -- which, as expected, violate the
null energy condition. The wormhole possesses an ergoregion, but no
superradiance. The geodesic motion in this spacetime is briefly discussed, and
the absence of closed circular null geodesics is demonstrated.
