We encounter space and time everywhere and at every instant in our lives. But we hardly notice and get concerned about it. We take their existence for granted. These things are neither visible nor can be sensed directly by our senses. However, they can be measured and this property is considered sufficient for all practical purposes. This simplicity breaks down, when we deal with vast distances of our universe, also at micro level of atomic particles and at incredible speeds. The reality of space and time is not easily comprehensible to human mind. Few ventured into its dark secrets and the concepts keep changing over the period since antiquity. We have advanced from absoluteness of Newtonian science to relativistic concepts of Einstein. However, something in it still defies explanation, its shear invisibility.