  We present an analysis of the period distribution of $\sim 1800$ Cepheids in
the Large Magellanic Cloud, based on data obtained by the MACHO microlensing
experiment and on a previous catalogue by Payne-Gaposchkin. Using stellar
evolution and pulsation models, we construct theoretical period-frequency
distributions that are compared to the observations. These models reveal that a
significant burst of star formation has occurred recently in the LMC ($\sim
1.15\times 10^8$ years). We also show that during the last $\sim 10^8$ years,
the main center of star formation has been propagating from SE to NW along the
bar. We find that the evolutionary masses of Cepheids are still smaller than
pulsation masses by $\sim 7$ % and that the red edge of the Cepheid instability
strip could be slightly bluer than indicated by theory. There are $\sim 600$
Cepheids with periods below $\sim 2.5$ days cannot be explained by evolution
theory. We suggest that they are anomalous Cepheids; a number of these stars
are double-mode Cepheids.
