What is hubble and why it is so important ?

Most of the space images of galaxies and stars give credits to Hubble for capturing it and this name is also mentioned in many space documentaries. I waned to ask what exactly is Hubble and why it had so much significance for the mankind.
Most of the space images of galaxies and stars give credits to Hubble for capturing it and this name is also mentioned in many space documentaries. I waned to ask what exactly is Hubble and why it had so much significance for the mankind.