  We present an analytical model which reproduces measured galaxy number counts
from surveys in the wavelength range of 500 micron to 2 mm. The model involves
a single high-redshift galaxy population with a Schechter luminosity function
which has been gravitationally lensed by galaxy clusters in the mass range
10^13 to 10^15 Msun. This simple model reproduces both the low flux and the
high flux end of the number counts reported by the BLAST, SCUBA, AzTEC and the
SPT surveys. In particular, our model accounts for the most luminous galaxies
detected by SPT as the result of high magnifications by galaxy clusters
(magnification factors of 10-30). This interpretation implies that
submillimeter and millimeter surveys of this population may prove to be a
useful addition to ongoing cluster detection surveys. The model also implies
that the bulk of submillimeter galaxies detected at wavelengths larger than 500
micron lie at redshifts greater than 2.
