Romila Thapar points out that an alleged equation of the Indus Valley civilization and the carriers of Vedic culture stays in stark contrast to not only linguistic, but also archeological evidence. She notes that the essential characteristics of Indus valley urbanism, such as planned cities, complex fortifications, elaborate drainage systems, the use of mud and fire bricks, monumental buildings, extensive craft activity, are completely absent in the Rigveda. Similarly the Rigveda lacks a conceptual familiarity with key aspects of organized urban life (e.g. non-kin labour, facets or items of an exchange system or complex weights and measures) and doesn't mention objects found in great numbers at Indus Valley civilization sites like terracotta figurines, sculptural representation of human bodies or seals.