Eye of Orion

The Eye of Orion was known to be one of the most tranquil places in the universe. Tegan likened it to "Earth after a thunderstorm." According to the Fifth Doctor. it achieved its calming effects from the "high bombardment of positive ions." (DW: The Five Doctors)

It may have been an entire planet, but was at least a specific spot on a planet.

The Doctor deliberately took Turlough and Tegan to the Eye immediately following their encounter with the Master and Kamelion in the time of King John (DW: The King's Demons). Soon after arriving, the Doctor began to experience what he called "cosmic angst", before discovering that his past selves were being separated from him.

The Doctor made several promises to take Evelyn Smythe to the Eye, but never managed to succeed. One one of several instances of her leaving the Doctor's side "permanently" — when Mel was also onboard — she specifically asked that he take her home by way of the Eye (PDA: Instruments of Darkness') The Doctor and Ace sat and meditated on the Eye of Orion during their search for the Timewyrm. (NA: Timewyrm: Revelation)

Martha Jones may have visited the Eye, as well. She has written that it used to be a thriving holiday resort, but after the Last Great Time War, it was converted into a shrine of the War, with only small memorial, nameless due to the many who died in the war. At this point, the only other structures were scattered ruins.

During its time as a shrine to the War, the Eye of Orion was still and quiet, covered in ruins, grass and mist.

The Doctor apparently imparted details about the Time War to Martha whilst there. (Martha Jones's Myspace blog)