Update, 6/1:: In Comments, Paul Day recommends checking out "Pavl Duke's Video Wall", which you can find by clicking an inauspicious button outside a seaside cottage in Cisthene. "I've tried to explain it people," he writes, "but it's one of those cases where words can never do it justice." I agree that it's pretty cool, and worth a click: Direct SLurl teleport at this link.
If someone asked you to send them to the coolest spot in Second Life, what SLurl would you give them to click? Can be a permanent location or sim, an ongoing event, a temporary sandbox construction, a commercial location, a non-profit resource, a provocative work of art or a fun game, a resting spot on a cliff by the sea, pretty much anything that inspires your personal fancy. Post in Comments, with a description of what the SLurl teleports you to. I'll highlight my favorites in an Update.