MASJID E AQSA
A Masjid or Mosque is the building in which Muslims worship Allahسبحانه و تعالى(The God). Throughout Islamic history, the mosque was the centre of the community and towns formed around this pivotal building. Nowadays, especially in Muslim countries mosques are found on nearly every street corner, making it a simple matter for Muslims to attend the five daily prayers. Al-Masjid El-Aqsa is an Arabic name which means the Farthest Mosque.
The Grand Mosques in Makkah and Madinah, the two sacred in Islam, draw millions of pilgrims annually. Al-Aqsa, the last of the three sacred sites Prophet Muhammad (peace be upon him) urged Muslims to visit, sees only a few thousand foreign visitors a year. These three mosques are the three for which it is prescribed to travel for the purpose of worship. The Prophet ﷺ said: “Do not travel or set out on journey(specifically) to any mosque except three: al-Masjid al-Haraam, Masjid al-Aqsa, and this mosque of mine.” Sahih al-Bukhari, Vol.2: 1189, Vol.3: 1996 and Sahih Muslim 1397 
It was built by Sulaymaan (peace be upon him), as stated in the hadith of Sunan al-Nasaa’i. Ten years after the Prophet Mohammad (pbuh) received his first revelation, he made a miraculous night journey from Mecca to Jerusalem and to the Seven Heavens on a white flying horse called Al-Buraq. Today, Muslims throughout the World use Mecca as the direction of prayers (Qibla). However, for 16½ months following the Prophet Mohammad's miraculous journey, Jerusalem was the Qibla. 
The Dome of the Rock was built by the caliph ‘Abd al-Malik ibn Marwaan in 72 AH. It also says in al-Mawsoo’ah (3/23): “The Dome of the Rock is situated in the middle of the plateau of al-Masjid al-Aqsa, which is in the southeastern part of the city of al-Quds (Jerusalem). It is a spacious rectangular plateau which measures 480 meters from north to south, and 300 meters from east to west. This plateau occupies approximately one-fifth of the area of the Old City of Jerusalem.
The mosque which is the place of prayer is not the Dome of the Rock, but because pictures of the Dome are so widespread, many Muslims think when they see it that this is the mosque. This is not in fact the case. The Mosque is situated in the southern portion of the plateau, and the Dome is built on the raised rock that is situated in the middle of the plateau.
Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) in Majmoo’at al-Rasaa’il al-Kubra, 2/61: “Al-Masjid al-Aqsa is the name for the whole of the place of worship built by Sulaymaan (peace be upon him). Some people started to give the name of al-Aqsa to the prayer-place which was built by ‘Umar ibn al-Khattaab in front of it. Praying in this prayer-place which ‘Umar built for the Muslims is better than praying in the rest of the mosque, because when ‘Umar conquered Jerusalem there was a huge garbage dump on the rock, since the Christians wanted to show their scorn for the place towards which the Jews used to pray . So ‘Umar issued orders that the filth be removedand a place of prayer for the Muslims was build it in front of it.’
‘Umar denounced Ka’b al-Ahbaar and called him the son of a Jewish woman because Ka’b had been a Jewish scholar and rabbi, so when he suggested to ‘Umar that he should build the mosque behind the rock, that was out of respect for the rock so that the Muslims would face it when praying, and veneration of the rock was part of the religion of the Jews, not the religion of the Muslims.
The Muslims’ fondness for the picture of the Dome may be because of the beauty of this building, but this does not excuse them from the resulting mistake of not distinguishing between the Mosque and the buildings that surround it. 
The rectangular Al-Aqsa Mosque is 144,000 square meters, 35 acres, or 1/6 of the entire area within the walls of the Old City of Jerusalem as it stands today. It is also called Al-Haram El-Sharif (the Nobel Sanctuary).
Al-Aqsa Mosque holds up to 400,000 worshippers at one time, bearing in mind that the space required for each person is roughly 0.8m x 0.5m to enable the submissive kneeling in prayer. On Fridays at noon, during the fasting month of Ramadan, and particularly the 27th of Ramadan (Lailat El-Qadr), the area is filled to virtual capacity.
There are 11 gates to Al-Aqsa Mosque: 7 of which are open. Of the 4 closed gates, one is the Golden Gate.
It was narrated from 'Abdullah bin 'Amr that the Messenger of Allah (ﷺ) said:"When Sulaiman bin Dawud finished building Bait Al-Maqdis, he asked Allah for three things: Judgement that was in harmony with His judgement, and he was given that. And he asked Allah for a dominion that no one after him would have, and he was given that. And when he finished building the Masjid he asked Allah, the Mighty and Sublime, that no one should come to it, intending only to pray there, but he would emerge free of sin as the day his mother bore him." Classed as Sahih by Shaikh Albani in Sunan an-Nasa'i 693
Al-Masjid al-Aqsa (in Jerusalem) was the first of the two Qiblahs(Direction of offering Salah), and is one of the three mosques to which people may travel for the purpose of worship. The Prophetﷺsaid: “Do not travel or set out on journey(specifically) to any mosque except three: al-Masjid al-Haraam, Masjid al-Aqsa, and this mosque of mine.” Sahih al-Bukhaari, Vol.2: 1189, Vol.3: 1996 and Sahih Muslim 1397
Abu Dharr (may Allaah be pleased with him) who said: “I said, ‘O Messenger of Allaah, which mosque was built on earth first?’ He said, ‘Al-Masjid al-Haraam [in Makkah].’ I said, ‘Then which?’ He said, ‘Al-Masjid al-Aqsa.’ I said, ‘How much time was there between them?’ He said, ‘Forty years. So wherever you are when the time for prayer comes, pray, for that is the best thing to do.’” Sahih Al Bukhari, Vol.4: 3425, Sahih Muslim, 520 and Sunan Ibn Majah 753
The Prophetﷺwas taken on the Night Journey (isra’) to Bayt al-Maqdis (Jerusalem), where he led the Prophets in prayer in this blessed mosque.
Allaah says: “Glorified (and Exalted) be He (Allaah) [above all that (evil) they associate with Him] Who took His slave (Muhammad) for a journey by night from Al-Masjid Al-Haraam (at Makkah) to Al-Masjid Al-Aqsaa (in Jerusalem), the neighbourhood whereof We have blessed, in order that We might show him (Muhammad) of Our Ayaat (proofs, evidences, lessons, signs, etc.). Verily, He is the All-Hearer, the All-Seer” Quran Surah al-Isra’ 17:1 
One prayer in al-Masjid al-Aqsa is equivalent to two hundred and fifty prayers offered elsewhere.
It was narrated that Abu Dharr (may Allaah be pleased with him) said: We were discussing when we were with the Messenger of Allaahﷺ, which is better, the Mosque of the Messenger of Allaah (peace and blessings of Allaah be upon him) or Bayt al-Maqdis (Jerusalem). The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “One prayer in my mosque is better than four prayers offered there (in Bayt al-Maqdis), and what a good place of prayer it is. Soon there will come a time when, if a man has a piece of land the size of a horse’s rope from which he can see Bayt al-Maqdis, that will be better for him than the whole world.” Mustadrak al-Haakim, 4/509; he classed it as saheeh and al-Dhahabi and al-Albaani agreed with him, as it says in al-Silsilah al-Saheehah, at the end of the discussion on hadeeth no. 2902.
One prayer offered in the Prophet’s Mosque is equivalent to one thousand prayers (offered elsewhere), so one prayer offered in al-Masjid al-Aqsa is equivalent to two hundred and fifty prayers.
With regard to the well-known hadeeth that says that one prayer offered there is equivalent to five hundred prayers, this hadeeth is da’eef (weak). Tamaam al-Minnah by Shaykh al-Albaani (may Allaah have mercy on him), p. 292. 
Allah knows best