Observational Extragalactic Astrophysics, with emphasis on optical, X-ray and infrared astrophysics: Studies of the properties of Supernova Remnants (SNRs) in different types of galaxies and in different wavelengths (optical, X-rays), probing for their interaction with the Interstellar Medium (ISM). Observational (optical) campaign of the entire SNR population in our Galaxy: the first atlas of Galactic SNRs is under construction which, along with existing multi-wavelength data, will shed light on their evolutionary trails and how they energize their surrounding medium.