What does it mean that the ancient capital of the Millennium often comes to Chang' an?

After visiting Xi 'an, it has become an unforgettable memory. Xi 'an is a nostalgic city.

Xi 'an's city slogan "Millennium ancient capital, often come to Chang 'an" is catchy, and with the vigorous publicity of the media, it was once widely known. It not only enhances the popularity of Xi, but also attracts tourists from all over the world.