Step 1: Identifying the structure.
The image shows a large hemispherical dome with ornate gateways (toranas), typical of Buddhist stupas.
Step 2: Explanation.
The Sanchi Stupa, located in Madhya Pradesh, was commissioned by Emperor Ashoka in the 3rd century BCE. It is a UNESCO World Heritage Site and one of the oldest stone structures in India.
Step 3: Conclusion.
Thus, the monument shown in the picture is the Sanchi Stupa.