  We have studied the nearby old pulsar PSR B1929+10 and its surrounding
interstellar medium utilizing the sub-arcsecond angular resolution of the
Chandra X-ray Observatory. The Chandra data are found to be fully consistent
with the results obtained from deep XMM-Newton observations as far as the
pulsar is concerned. We confirm the non-thermal emission nature of the pulsar's
X-radiation. In addition to the X-ray trail already seen in previous
observations by the ROSAT and XMM-Newton X-ray observatories, we discovered an
arc-like nebula surrounding the pulsar. We interpret the feature as a bow-shock
nebula and discuss its energetics in the context of standard shock theory.
