Ok, so, from everyone's great examples, the Seven Criteria for Galactic Wonders of Charted Space could be:
Unique/Important Race Homeworld
examples: Terra (true homeworld of Humaniti), Muan Gwi, Vland, Zhladt, Kirur, etc...
Unique Natural/Geological/Planetary Feature
examples: Singing Crystaline Caves of Deimnos, Giant Trees of Ranther
Unique Spacial Feature
examples: Black Hole in Vargr Space
Unique/Outstanding Technological Feature
examples: Hinterworlds Ringworld, Dyson sphere, Lair Beanstalk, Grav Platforms of the Gas Giant Terbus III, Kempler's Rosette
Outstanding Ancient Site
examples: Andory
Outstanding Racial Relic/Site
examples: Darrian Sun/Homeworld, The Domed Pleasure Cities of Stellatio 7 (he he he - non-canon, of course)
Unique/Outstanding Government Headquarters
examples: 3I Capitol - Imperial Palace
A tour of all of these sites could take a lifetime. Or several. I think once T20 comes out, I might start doing a weekly post of a Galactic Wonder.
Later,
Scout