Whatever one calls it ---- but it really is a not a circle though the guide books say it is... I read somewhere that it really is a mossy green triangle but calling it that is far less marketable then the Golden Circle - - nevertheless, even the locals said 'go' --- its WORTH the time - and it doesn't even take that much time.
So triangle. Circle. Or square. Go there.
First part of triangle:
Pingvellir - a rift valley bounded by cliffs
Pingvellir - means Parliament Fields - where Icelandic parliament met for first time back in the day...
The Yosemite of Iceland.
With the largest natural lake.