One of the angels, who dispensed a bowl of God's wrath, spoke to the apostle John and explains the meaning behind Babylon (Rev 17:1-18:24).

Babylon is portrayed as "the great harlot" (Rev 17:1), and "the Mother of Harlots, and Of the Abomination of the Earth" (Rev 17:5).

From a theological perspective, a "harlot" was a term God used to refer to His people that were unfaithful to the Mosaic Covenant by worshiping other gods (Ex 34:14-16; Lev 20:4-6; Deut 31:15-17). Here Babylon is portrayed as something more than an individual non-Believer. It is "the great harlot" who leads others, including kings, to be immoral (Rev 17:15-18). It is a lifestyle that attracts all cultures and people and is intoxicating and pleasurable (Rev 18:2-3).

What the angel describes figuratively as "Babylon," the apostle John described elsewhere in the words of Jesus as "the world."

Do not love the world nor the things in the world. If anyone loves the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh and the lust of the eyes and the boastful pride of life, is not from the Father, but is from the world. The world is passing away, and also its lusts; but the one who does the will of God lives forever. (1 John 2:15-17)

Babylon represents the world, a secular culture that denies the existence of God and sin. In lieu of God and His imperative to be holy (Lev 20:26), a life motivated by pride and power derived by human achievement.

Babylon has a special significance to God. After Noah's Ark and the Flood, human beings attempted to build a tower and make a name for themselves. But it wasn't simply building a tower, it was building a tower "into heaven" and seeking some recognition akin to God.

As the apostle John learns of Babylon from the angel who dispensed a bowl of God's wrath, he is learning of God's judgment, and the end of this evil influence, culture, and mindset.

For deeper study:

The Doom of Babylon