The Day of Shadows

The Day of Shadows is the most infamous day in Ravnican history to date. Often spoken of as the 'worst day' of many people's lives, the entirety of Ravnica experienced strange and disasterous occurrences in a single 24 hour period resulting in a massive loss of life and property.
The Day of Shadows began as all other days in Ravnica do, with the hustle and bustle of the city coming to life from the night before. As lights and driftglobes soared over the cavern, people began to start their day as they usually do. Izzet boiler engines fired up, starting the laboratories and the monorail system, while flowers blossomed and began pollenating in the Selesnya Conclave. Orzhovan priests began their rites for the day, the banks opening their doors for hopefuls looking to secure a loan for their own personal business adventures, or guild business in general. The Rakdos Labor Union set to work on construction sites, running the public services of the city, like always.
House Dimir had been investigating a derelict ruin unearthed by Golgari trash collectors, documenting its estimated date and purpose of creation. While investigating, a sigil activated in the derelict ruin, sending a low humming sound throughout the entire 10th District. The hum grew louder, causing buildings to quake and crack under the vibrations. Soon, the humming died, but the worst was yet to come. Only a few people had sustained injuries up to this point, many from falling debris from loose balconies, and none had been killed by the incident.
Then, the driftglobes stopped working. One by one, they fell from the sky above, crashing into the ground and shattering into thousands of pieces. All over the city, people were struck by falling driftglobes in the darkness, killing a few dozen and injuring even more. As the city fell into darkness, crime rates skyrocketed^[1], many blaming Krenko for the insurrection of criminal activity. In just a few hours, the 10th District of Ravnica was in near ruin, with open looting, violence, and darkness consuming the residents.
As the driftglobes went out, so did the power grid system created by the Izzet. When this happened, many temperature sensitive experiments reacted violently, causing a chain reaction of explosions in dozens of Izzet towers across the 10th district, killing hundreds bystanders. The Simic Combine beast cages and birthing pods were also depowered, releasing the unfinished monstrosities into the open city streets. Many Simic deepsages and front researchers were killed by their own creations. During the riots, many of the Guildless blamed the Azorius Senate, stating their slow political and decision making processes had allowed their city to fall to ruin, and a riot was staged outside the Senate. Many senators and politicians were killed in these riots, only being quelled by elite Boros Wojek and Skynights. However, the Boros were not without losses either. Many elite guards lost their lives defending innocents from explosions, riots, and from crime masterminded by Krenko. Agrus Kos, the Blade of the Legion, was seen heading into the riots at the Azorious Senate to offer his sword against those who would harm the Azorius politicians. He was struck in the neck by a rogue arrow from the riot crowd, killing him almost instantly. In his death, Tajic was given a battlefield promotion to Blade of the Legion and quelled the riot shortly after.
The Selesnya Conclave experienced a new disease called Rootrot, a destructive pathogen that almost instantaneously killed living plant life and putrefying the ground, preventing anything from growing there. Many of the Voda were killed due to the disease, leaving conclave settlements without a leader, tossing them into ruin as well. The Simic were able to construct a makeshift vaccine months afterwards, eradicating the pathogen entirely.
In all, each guild suffered tragic losses of both property and life, except for House Dimir^[2]. Because of this, and the origin of the events this day, House Dimir was publically scrutinized for shady dealings with private investigators, of which a connection was established between House Dimir and Krenko's drug smuggling operations underneath the city^[3]. In addition to these findings, the public were able to ascertain certain members of House Dimir's publication of the newspaper had given substantial money to Azorious senators to allow for increased distribution of the daily paper to occur multiple times a day, further padding House Dimir's income revenue^[4]. To this day, the public still scrutinized House Dimir for their involvement^[5] in Krenko's drug smuggling business and the infiltration of the Azorious Senate^[6] for monetary benefit, but this has not stopped House Dimir from publishing the daily news to all districts of Ravnica as they have always done.
It took months for the 10th District to recover, though many still remember the day vividly.
^[1] Sources from House Dimir report a staggering 322% rise in crime rates of populated areas of the 10th district during the Day of Shadows.
^[2] House Dimir suffered the loss of 3 significant reporters at the derelict ruin site, not to mention many injuries sustained during the Day of Shadows various catastrophes.
^[3] There is no evidence to support these claims, only unreliable eyewitness accounts and rumors.
^[4] Though donations were made to the Azorius Senate, the purpose of said donations were to better fund the lawmaking process in general, not specifically to benefit House Dimir. No evidence exists of a stated purpose for these donations.
^[5] Alleged (albeit unsupported with evidence).
^[6] Donations were made with good intent to help fund lawmaking processes in Ravnica.