Vatican–Avignon Pipeline

The Vatican–Avignon pipeline (バチカン–アヴィニョン パイプライン) is a ley line that connects the Vatican and Avignon, as a "pipeline" for magical power between the two cities.

Principles
It was constructed during the, when the Pope moved from the into Avignon, due to the fact that there were things that the Pope had to that could only be done in the Papal States. Things like the investiture of Cardinals and various ecumenical council meetings could be carried out by a representative. But things that had to be done within the Papal State, in buildings within the Papal State, or with certain spiritual items in the Papal State couldn’t be done from Avignon in the same way. They couldn't create the same devices in Avignon that they had in the Papal State, but by creating a magical pipeline to Avignon, they could control the devices in the Papal State long distance.

Background
The pipeline was constructed during the Avignon Papacy, when the Pope moved from the Papal States into Avignon. After the Pope moved back from France at the end of the Avignon Papacy, the exact fate of the pipeline is unknown, as according to Itsuwa either the Church left a facility connected to it or may have reconnected after it has been severed.

Document of Constantine Arc
Regardless, the pipeline is later used by the Roman Catholic Church to use the Document of Constantine in the Palais des Papes, one of the facilities where pipeline can be accessed by them, and started the worldwide October riots. One of the points where the pipeline can be found is within a museum in Avignon.

It is unknown if the ley line survived the onslaught brought by the invasion of Academy City after the perimeter surrounding Avignon was turned into molten rock by HsB-02 planes' Earth Blade and the partial destruction of the Palais des Papes.