The Platform, General
On this platform, the Terhermelern were watching the spread of North American tribes and the rise of city states along the Nile, Tigris and Euphrates and the Yang-Tze River, when the Mellor war hit.
All Alt Rings on this Platform lead to the Olentangy Indian Caverns outside of Dublin Ohio, which itself is near Columbus. The users were interested in the area around Cleveland where the Cuyahoga River goes into Lake Eerie, under the theory that fresh water, the lake shore and the river would draw settlers. The Olentangy Indian Caverns were chosen as the best place to locate a ring to support observations. It's about 140 miles south of Cleveland.
In all instances, the ring placers dug a new chamber at the back of the caverns, a level up. This new chamber is hidden by an artful fold in the roof of the lower chamber so you can't see it's there, unless you're right underneath it, and even then, upper and lower roof are color matched so it would be easy to over look. In Alts with humans - there is a hologram blocking direct sight of the new chamber - powered by environmental heat - this leaves the lower chamber slightly cooler. The Indians of the area used the cavern to store food.
The Alt rings have stayed "Close" to the prime world in terms of probability, and so have tracked the Prime until they are in alts as seen - over hundreds of years, as the histories diverge, the rings would "move" to other close alts - until used. The more often it's used, the more an Alt ring is "Anchored" in its alt.
If the Prime World's history diverges too far from a well used Alt - the users may come to find different Alternate world through that ring - and a new node next door - now the former alt is a prime.
But how the Node system knows to do this and what criteria it uses to make this decision is mysterious.
South - 6:00 O'Clock Ring to 0-Prime Platform
No One Home This ring looks like a treetrunk wrapped into a circle.
Survivors of the Long Night This ring appears to made of wood and leather bindings
West - 9:00 - Big Ring to +1 Alt
New Wallonia: This ring looks like wood with riveted iron binding, with pattern burned into the wood, Curliques and swooping lines.
Dublin, OH 2020 This Ring also looks like it was designed by Masamune Shirow. There is a data jack on the right hand side that fits computers from this world.
North - 12:00 - Big ring to 0 System Platform
WPC - ring looks like the stainless steel closing side of a vault.
Stand +30 - Ring looks like the closing ring of a submaring style hatch of epic size, faded paint and rust.
East 3:00 - Ring to -1 Alt
Cold War 1879 - Appears to be solid Cold riveted Iron with rows of rivets on the outside and inside
French Empire - Ring looks like an Art Deco Sculpture in Marble