An overview of the HST Treasury Program on the Orion Nebula

I will give an overview of the HST Treasury Program of the Orion Nebula Cluster. This project, completed in May 2005, represents the single largest investment of HST time (104 orbits) ever dedicated to star formation. The survey has imaged 1/6 of a square degree, nearly centered on the Trapezium stars, with ACS, WFPC2 and NIC3 in parallel. This cornerstone field has been mapped with unprecedented sensitivity (23-24 mag), dynamic range, spatial resolution, and spectral coverage (9 filters from U to H). The spectacular HST images provide the richest, most accurate and unbiased dataset of stellar photometry for pre-main-sequence objects ever made.