Lothlórien

Lothlórien, also known as Lórien, was the vast woodland realm of the Galadhrim elves located near the lower Misty Mountains in northern Middle-earth. It was first settled by the Nandor, but they were later joined by a small number of Ñoldor and Sindar under Celeborn of Doriath and Galadriel, daughter of Finarfin. It was located on the River Celebrant, southeast of Khazad-dûm, and was the only place in Middle-earth where the golden Mallorn trees grew.
Galadriel's magic, later revealed as the power of her ring Nenya, enriched the land and made it a magic forest into which evil could not enter without difficulty. The only way that Lothlórien could have been conquered by the armies of Mordor is if Sauron had come there himself.