  We propose a MIDEX-class space mission with the goal to find and characterize
roughly 10,000 transiting planets. When transits occur, a much more detailed
characterization of the planet is possible and so a large data base of
transiting planets will provide planets with a large range in periods and radii
for follow-up studies. Our survey will be all-sky and focused on stars brighter
than V=14.8. Down to V=12, LEAVITT will be able to detect Neptune-sized
objects. Because of it's high cadence, LEAVITT is about 100 times more
sensitive at detecting transits than GAIA, while it will find more than 20
times as many transits as KEPLER. LEAVITT has multi-band photometric capability
implemented via a low-resolution dispersive element which can obtain 0.2% (2
mmag) photometry down to V=14.8. LEAVITT's high multi-band photometric accuracy
reduces the number of false-positives significantly.
