The Great Nebula in Orion - M42
This is one of the visibly largest objects in our night sky but it requires a long exposure to see all the nebulosity, it is located at what appears to be the central star of Orion's sword which is in fact a star factory made up of massive amount of gas, mainly Hydrogen Alpha.
This is 1,344 light years away so you're looking back in time 1,344 years.