  Magnetic-field reconnection is believed to play a fundamental role in
magnetized plasma systems throughout the Universe1, including planetary
magnetospheres, magnetars and accretion disks around black holes. This letter
present extreme ultraviolet and X-ray observations of a solar flare showing
magnetic reconnection with a level of clarity not previously achieved. The
multi-wavelength extreme ultraviolet observations from SDO/AIA show inflowing
cool loops and newly formed, outflowing hot loops, as predicted. RHESSI X-ray
spectra and images simultaneously show the appearance of plasma heated to >10
MK at the expected locations. These two data sets provide solid visual evidence
of magnetic reconnection producing a solar flare, validating the basic physical
mechanism of popular flare models. However, new features are also observed that
need to be included in reconnection and flare studies, such as
three-dimensional non-uniform, non-steady and asymmetric evolution.
