There are three main mosques in Islam.
The first is the Masjid al Haram or Sacred Mosque in Makkah at the centre of which is The Kaaba often referred to as the First House because it was the first House of Allah (God) to be built on earth.
The second is the Masjid an Nabbi or Prophet's Mosque in Al Madinah which was first built by the Prophet himself may peace and blessings be upon him with the help of his companions just after his arrival in Madinah after making the Hijra or migration from Makkah
The third is Masjid al Aqsa or the Further Mosque in Jerusalem where the
Quba as Sahra or Dome of the Rock also stands
The mosque is the heart of the Muslim community and as such there are a great many mosques throughout the Muslim world. Many of these are masterpieces of architecture and they span a huge range both in terms of size as well as age.
You can find out more about some of the mosques of the world by searching through the following sites on line:
For photos of many well known mosques try:
For an on-line tour of Al Aqsa mosque try:
www.palestinehistory.com/sights/aqsa/aqsa.htm
also:
To search for many sacred places including mosques try:
For a directory of mosques in the UK try: