We present the results of the photometric analysis of a large part of the main body of the Small Magellanic Cloud. Using the 6.5m Magellan Telescope at the Las Campanas Observatory in Chile, we have acquired deep B and I images in four fields (0.44deg each in diameter), yielding accurate photometry for 1068893 stars down to 24th magnitude, with a spatial resolution of 0.20arcsec per pixel. Colour-magnitude diagrams and (completeness-corrected) luminosity functions have been constructed, yielding significant new results that indicate at least two discrete star formation events over a period from 2.7 to 4Gyr ago. Also, we have derived star formation rates as a function of look-back time and have found enhancements of SF between 4 and 6Gyr and at younger ages.