In general, gravity also gets stronger as you get closer to the center of a massive object, but it turns out that the effect of having less mass closer to the center than you are is more important. At the exact center of the Earth, the gravitational field is actually zero.

Gravitational Potential Energy is determined by three factors: mass, gravity, and height.

gravitational potential energy

Because the mass of the Earth is two orders of magnitude greater than the mass of the Moon, the centre of gravity of the Earth-Moon system actually lies within the body of the Earth; indeed, it is around 1700 km below the surface of the Earth.

The central point of the Earth is over 6,000km down, and even the outermost part of the core is nearly 3,000 km below our feet. The deepest hole we’ve ever created on the surface is the Kola Superdeep Borehole in Russia, and it only goes down a pitiful 12.3 km.

Armstrong further says that the Kaaba was thought to be at the center of the world, with the Gate of Heaven directly above it.

The “Mecca: the Center of the Earth, Theory and Practice” conference was organized and attended by Muslim theologians and other religious officials from across the world.

Kaaba, also spelled Kaʿbah, small shrine located near the centre of the Great Mosque in Mecca and considered by Muslims everywhere to be the most sacred spot on Earth. …

Shia Muslims number 200 million and are the second largest denomination in the faith. Many perform the hajj, and they also travel to Iran, Iraq and beyond to visit holy sites. In Mina, Saudi Arabia, hundreds of Shias have travelled from Britain to perform the hajj.

Muslims believe that Abraham—known as Ibrahim in the Islamic tradition—and his son, Ismail, constructed the Kaaba. Tradition holds that it was originally a simple unroofed rectangular structure. The Quraysh tribe, who ruled Mecca, rebuilt the pre-Islamic Kaaba in c. 608 CE with alternating courses of masonry and wood.