Bright Causeway

The Bright Causeway is a central transit and power network linking together the major cities of the League of Nine. It is arguably the greatest creation of humanity on Ethos.

Terminology
The Bright Causeway is the network in sum total. A Bright Causeway is a particular portion of the network.

Functionality
The Bright Causeway's initial primary function was to facilitate long distance overland travel. As the League of Nine exists wholly east of the Krinner mountains, its inhabitants had no access to the Astral Gate network. The Causeway was designed as a response to the Astral Gates, relying on the known magical school of evocation rather than the Gates' translocation.

The Causeway is ultimately a massive evocation device. It absorbs energy from sunlight and transfers it to any living being on the Causeway. As a result, any living creature can move along the Causeway during daylight without experiencing fatigue. This allows League couriers, merchant, supply wagons, and even armies to run at full speed from dawn until dusk each day, greatly decreasing travel times. This was the Causeway's primary function until 1664, when it was realized how much of the Causeway's energy was collected but never utilized.

In an event that would later come to be called Ascension Day, each of the remaining Consuls were grafted into the Causeway's energy network on March 8th, 1665. This gave each consul a nearly limitless supply of motive power, provided by the vast expanse of the Causeway not in use at any given time. Ascension proved to be the moment when the League gained a real opportunity to defeat the Alliance, despite the Alliance's superior numbers.

Here Be Spoilers
Halil states that, if the achievements of the Eldest were a 10, the Bright Causeway is the first thing humans have done to reach a score of 1.