the world's largest ancient sundial samrat yantra at the jantar mantar observatory.

landmark architecture facade largest ancient sundial samrat yantra jantar mantar observatory world's curved marble surface measurements visible high staircase blue sky background india yantra sun dial observatory jaipur sundial mantar brihat wandering calculation white circular measure extraordinary marking astronomical clock marble science unique sky jantar curve scale sandstone measurement unesco observation time instrument astrology unesco world heritage stairway astronomy steps tall large india high staircase famous tower culture blue historic historical stone ancient old