In daily prayers, Muslims face the Kaaba in Mecca, a cube-shape stone building that was built by Prophet Abraham and his son Prophet Ishmael in the same foundations where Prophet Adam is believed to have built the first place of worship.
Is that mean that Muslims worship Kaaba? Muslims do not worship the Kaaba and there is nothing inside of it. Muslims neither worships Muhammad neither pray through him. Muslims only worship the Unseen and Omniscient Creator, Allah.
One of the pillars of Islam, is doing hajj (pilgrimage) to the Kaaba in Mecca. Currently hajj is made by over 3 million Muslims from all over the earth.
Allah says in the Quran :
وَلِلهِ عَلَى النَّا سِ حِجُّ الْبَيْتِ مَنِ اسْتَطَا عَ اِلَيْهِ سَبِيلاً
“Hajj to the House is duty to Allah for mankind, for him who can find away to do it.” (The Noble Quran, 3:97)
The rituals of hajj commemorate the struggles of Prophet Abraham, his wife Hagar and their son Ishmael in surrendering their wills to God.
One night Prophet Abraham had ad dream that he sacrificed his son, Ishmael. Abraham was a truthful Prophet and his dream was a true dream. Prophet Abraham decided to do what Allah had commanded him to do in the dream, asked Ishmael, “My son, I saw in a dream that I must sacrifice you, what do you think about this?” For this question Ishmael replied, “Do as you are ordered, Allah willing, you will find me resolute.”
When Prophet Abraham reached Mina, he was ready for the sacrifice of Ishmael. Prophet Ishmael laid down on the ground and Prophet Abraham put the knife to Ishmael’s throat. By doing this, Abraham showed that he loved Allah more than his own son. When Abraham had passed the test, Allah sent the Angel Jibreel with a ram to spare Ishmael’s life. Allah was pleased with Prophet Abraham, so He commanded Muslims to make sacrifice of an animal in remembrance of this incident.
巡礼は、特別な価値のある行為としてみなされており、人々に懺悔や罪の赦し、また個人的献身行為や精神的高揚の促進などにおける最高の機会を与えてくれます。イスラームにおいて最も神聖な都市であるマッカへの巡礼は、経済的・肉体的に余裕のある全てのムスリムが一生に一度は行わなければならない義務行為です。毎年地球上のあらゆる地域から300万人を越す人々が、異なる民族同士が出会うこの集まりにやってきます。巡礼者たちは特別の装いをします。それは縫い目のない二枚の布で、これによって階級や文化の違いはなくなってしまい、全ての人々がアッラー の前で等しく立つのです。ハッジの儀式は、預言者イブラヒーム(アブラハム)にその源泉を見ることができます。例えばカアバ神殿の周りを7周したり、イブ ラヒームの妻ハージャルが水を求めて行ったように、サファーとマルワの丘の間を7回行き来したりします。巡礼者たちは後にアラファートの平野に集い、とも にアッラーの許しを求めて祈ります。その姿はしばしば審判の日の光景にたとえられます。

[The Kaba, in Mecca Saudi Arabia, image source : http://www.muslimahjapan.com documentation]