Parhelion
The Parhelion is a skyship and great hall where the Boros angels reside; it was at first constructed in an attempt to find Ravnica's planeswalker visitors who had stopped coming, but when the angels flew it to the edge of Ravnica's existence they encountered only emptiness. It was later used only as the Boros headquarters.
It was located high above the city of Ravnica, amongst the clouds. In times of war, the Parhelion would descend and dock with Sunhome. The angel Feather was restricted from the Parhelion for some unknown reason, and as punishment her wings were bound and she was forced to serve the Wojek, amongst normal mortals.
An unknown time later, Szadek, who was enslaved by Augustin IV at the time, managed to gain access to the Parhelion and managed to kill its residents. He then planned to use it to destroy Prahv and the Guilds. Although his plan was stopped by Agrus Kos, the Parhelion was destroyed.
It is currently unknown if there were efforts to reconstruct or repair it.