In the gospel of Mark 13:24 the Greek θλιψις (thlipsis) is used. This word is also used in other apocalyptic passages in the New Testament: in Matthew 24:29 and in Revelation (especially 1:9 and 7:14). Θλιψις is generally translated as ‘oppression, affliction, tribulation’ (BADG p. 457), but I think that in these apocalyptic fragments it is a code word for the destruction of the Temple in the summer of 70 CE. So I believe that an event is meant instead of a period, and therefore ‘catastrophe’ would be a proper translation in these instances. Revelation 7:14 says οὗτοί είσιν οἱ ἐρχόμενοι ἐκ τῆς θλίψεως τῆς μεγάλης (houtoi eisin hoi erchomenoi ek tès thlipseōs tès megalès), ‘these are they who have come out of the Great Catastrophe’. The combination of μέγας and θλιψις points in the direction of the suggested translation, as this was the greatest catastrophe thinkable. In Revelation 1 θλιψις (in verse 9) is associated with ‘the day of the Lord’ (in verse 10), the catastrophic turn of the era in August 70 CE.
In my opinion the apocalyptic texts of the New Testament – the Synoptic Apocalypse in Mark, Luke an Matthew, and the book of Revelation – together with the last, apocalyptic chapter of the early Christian Didache, contain essential information on the birth of Christianity in an encrypted way.