Luke 13:1-5 is an interesting passage, it refers to an event and disaster that are not recorded in the other gospels.
1Now there were some present at that time who told Jesus about the Galileans whose blood Pilate had mixed with their sacrifices. 2Jesus answered, “Do you think that these Galileans were worse sinners than all the other Galileans because they suffered this way? 3I tell you, no! But unless you repent, you too will all perish. 4Or those eighteen who died when the tower in Siloam fell on them—do you think they were more guilty than all the others living in Jerusalem? 5I tell you, no! But unless you repent, you too will all perish.”
In verses 1-3 there is reference to sacrifices mixed with the blood of some Galileans. Barnes and Gill both indicate in their commentaries that it is likely that Pilate killed them while they were offering sacrifices, resulting in the mingling of blood.
In verses 4 and 5, Jesus refers to a tower in Siloam, which I assume at the time had recently fallen and killed 18 people.
There doesn’t seem to be much known about what happened, I just find these two references interesting because Jesus most often uses parables to make a teaching point, but here he has used two recent events, the first brought up by people asking a question and the second to emphasis the point.