Oral title: The Galactic bulge as seen by the OGLE survey

Oral abstract: The Galactic bulge has been continuously observed by the Optical Gravitational 
Lensing Experiment (OGLE) since 1992. Currently, the OGLE project monitors the brightness of 
about half a billion stars in this region of the sky. These data provide us with a tool to study the 
structure of the bulge, to describe the star formation history, to measure the distance to the center of 
the Milky Way, to trace the metallicity distribution, and to map the interstellar extinction. Gravitational 
microlensing events have been used to probe the chemical composition of dwarfs in the central 
regions of the Galaxy and to detect exoplanets. Hundreds of thousands of new variable stars have 
been identified, including objects of previously unknown classes.