Daniel's 70 Weeks shows that God determines the redemptive history of Israel in Cycles of 70*7=490 years. In particular it defines the last of these Cycles as running from the Ezra Decree to rebuild and restore Jerusalem in 458 BC and concluding with Messiah's sacrificial death making final atonement for our sins in AD 33.
Daniel's 70 Weeks or 490 Years (Daniel 9:24-27).
v24 "70 weeks are determined
for your people and for your holy city,
To finish the transgression,
To make an end of sins,
To make reconciliation for iniquity,
To bring in everlasting righteousness,
To seal up vision and prophecy,
And to anoint the Most Holy.
v25 Know therefore and understand, that from the going forth of the command to restore and build Jerusalem (BC 458) until Messiah the Prince, there shall be seven weeks (49 years) and 62 weeks (434 years). The street shall be built again, and the wall, even in troublesome times.
v26 And after the 62 weeks Messiah shall be cut off, but not for Himself; and the people of the prince who is to come shall destroy the city and the sanctuary. The end of it shall be with a flood, and till the end of the war desolations are determined.
v27 Then he shall confirm a covenant with many for one week;
But in the middle of the week he shall bring an end to sacrifice and offering. And on the wing of abominations shall be one who makes desolate, even until the consummation, which is determined, is poured out on the desolate."
For an intesting confirmation that the year of the Cross (the end of the 490 years) is AD33 go to The Day the Sun stopped shining.
For an exposition of the 70 Weeks (including a discussion of the correct starting point) click here.