Omphalos is the stone that represents the center of the world, revered in ancient times at various locations. It is a visible expression of the place where, according to the beliefs of many cultures, the underworld, earth, and sky are in closest contact. The land, city, or ruler that possessed a supposed Omphalos enjoyed high esteem and, with increasing veneration, also wealth. The presented material primarily focuses on the Indo-European area and illustrates the preferred forms of visualizing the concept of Omphalos in architecture and urban planning. A less spectacular variant of the idea of centering is indicated by the stone arrangements found in market and town squares in Central Europe, particularly in the Rhine-Meuse region. These embedded monoliths, known as blue stones, serve no public function and have only been preserved in the urban landscape for conservation or tourist reasons. Their existence is particularly intriguing as they are placed in central locations within the urban fabric, often at the intersection of former main roads. This monograph sheds light on the various connections of these rock blocks with ancient world centers and includes a collection that presents urban navel stones for the first time in a cohesive manner.