Is ramadan the holy city of muslims?

Answer 1

No. Ramadan is a month of fasting, not a place.

Holy Sites of Islam
Islam sees the entire world as a holy place in which worship can occur (with the exception of certain indoor spaces like bathrooms which are not clean or dry). However, there are certain places of additional holiness to which Muslims go to amplify the strength of their prayers or to feel closer to God .

The three biggest holy places are:

1. The Masjid al-Haram or Grand Mosque in Mecca, Saudi Arabia in which sits the Ka'aba or Black Cube. Muslims are required, if financially able, to visit the Ka'aba once in their lives in the pilgrimage known as the Hajj. The largest congregational open prayers are done in Mecca and Medina during the Hajj. Refer to related question below on how to perform the Hajj.
2. The Masjid al-Nabawi or the Prophet's Mosque in Medina/Yethrib, Saudi Arabia. (The city is known by both names.) This was the second mosque built in the history of Islam, and built adjacent to Muhammad's house in Medina/Yethrib. It established the proper shape and style of mosque building as well as being Muhammad's final resting place.
3. The Haram al-Sharif and the Al-Aqsa Mosque or the Dome of the Rock and the Distant Mosque in Jerusalem, Israel/Palestine. This is the place where prophet Muhammad was ascended to heaven as God miracle.

Additionally, there are famous mosques which hold great prestige or value such as the Jame'a Bani Umayya al-Kabir or the Great Umayyad Mosque in Damascus, Syria or the Jame'a Al-Azhar or Flower Mosque in Cairo, Egypt. There are also special mosques that are significant primarily to only Shiites such as Abbas Mosque, in Karbala, Iraq. These are called The "Ahl Al-Bayt".

Finally, the tombs of Sufi saints are also seen as limited holy places to Muslims and there are some towns, like Moulay Idriss, Morocco which have become sanctified due to the burial of an Islamic Saint.

Answer 2

It is not a city of the Muslims. It is the month of fasting for the Muslims.