The Kaaba (Arabic: الكعبة al-Kaʿbah; is a cuboidal building located inside the al-Masjid al-Haram mosque in Mecca, Saudi Arabia. The mosque was built around the original Kaaba.

The Kaaba is the holiest place in Islam. The qibla, the direction Muslims face during prayer, is the direction from their location on Earth towards the Kaaba. It is around the Kaaba that ritual circumambulation is performed by Muslims during the Hajj (pilgrimage) season as well as during the Umrah (lesser pilgrimage).

The Kaaba is a large masonry structure roughly the shape of a cube. It is made of granite from the hills near Mecca, and stands upon a 25 cm (10 in) marble base, which projects outwards about 30 cm (1 foot). Approximations for the structural dimensions are: 13.10 m (42.98 ft) high, with sides measuring 11.03 m (36.19 ft) by 12.62 m (41.40 ft).[3][4] The four corners of the Kaaba roughly face the four points of the compass.

In the eastern corner of the Kaaba is the "Rukn-al-Aswad" (the Black Stone or al-Ħajaru l-Aswad), generally thought to be a meteorite remnant; at the northern corner is the "Rukn-al-Iraqi" ('The Iraqi corner'); at the west lies "Rukn-al-Shami" ('The Levantine corner') and at the south "Rukn-al-Yamani" ('The Yemeni corner').

It is covered by a black silk curtain decorated with gold-embroidered calligraphy. This cloth is known as the kiswah; it is replaced yearly.The Shahadah is outlined in the weave of the fabric. About two-thirds of the way up runs a gold embroidered band covered with Qur'anic text.
( http://en.wikipedia.org/wiki/Kaaba )

And Here is the picture of Kaaba