Masjid-ul-Haram (the Ka'aba) in Makka Mukarrama, Masjid-un-Nabi in Madina Munawwara, and Masjid-i-Aqsa in Jerusalem are the most sacred places of worship for the Muslims.
Muslims go to Mosques and Christians go to churches.
Muslims don't worship any building. Even, the Kaaba (that is the most sacred Islamic building) is not worshiped by Muslims but respected and honored by Muslims. If you wish to read about places where Muslims worship (both houses of worship and sacred sites) read the Related Question below.
There are three places of worship where Muslims should go: Makkah, Madina and Masjid Al Aqsa in Jerusulum
I presume you mean Muslims. The place of worship for Muslims is called a Masjid, also called a Mosque in some places.
no one knows for sure?
Places where people meet to pray to their god(s).
Where you worship depends on your religion, not your nationality. People in Poland worship in many different types of places. Most Christians in Poland worship in a church, because Christians worship in a church. Most Jews in Poland worship in a temple or synogogue, because that is where Jews worship. Muslims in Poland worship in Mosques, because that is where Muslims worship. Many religions (including Christians, Jews, and Muslims) also worship at home.
Arabic calligraphy .
Yes, Muslims go to the Mosq on Fridays
For Muslims -Mosque, for Hindus-Mandir, for Christians Church etc. Each religion has different name for its place of worship
The Muslims may offer prayer at any neat and clean place, at home, at office or in open ground. Anyhow, they have built special buildings for this purpose where they offer prayer in a group led by a scholar called Imam. These places are called Mosques.
No. Synagogues are Jewish houses of worship. Muslims pray in a mosque.