All earthly kingdoms eventually end. Nebuchadnezzar's dream suggested that Babylon would fall and a new kingdom would rise (Daniel 2:39).
After Nebuchadnezzar died in 562 BC, violence and corruption grew in Babylon's palaces. During Belshazzar's feast in 539 BC, they even defiled God's holy vessels. God's judgment came quickly that night (Daniel 5:30), and the next kingdom took over (see 2:32, 39; 5:31).