There is an attempt on the emperor's…

There is an attempt on the emperor's life in St. Petersburg by Dmitry Karakozov in April 1866.

To commemorate his narrow escape from death (which he himself refers to only as "the event of 4 April 1866"), a number of churches and chapels will be built in many Russian cities.

Viktor Hartmann, a Russian architect, even sketches a design of a monumental gate (which is never built) to commemorate the event.

Modest Mussorgsky will later write his Pictures at an Exhibition; the last movement of which, "The Great Gate of Kiev", is based on Hartmann's sketches.

Living in fear, Alexander sequesters himself with access limited to only a few favorites.