Sanchi Great Stupa having relics of the Buddha was originally commissioned by Emperor Ashoka in 3rd century BCE and is one of oldest stone structures in India

Note that Sanchi is pronounced as Saanchi.

Given below are relevant extracts from https://en.wikipedia.org/wiki/Sanchi :

Sanchi is a Buddhist complex, famous for its Great Stupa, on a hilltop at Sanchi Town in Raisen District of the State of Madhya Pradesh, India. It is located, about 23 kilometres from Raisen town, district headquarter and 46 kilometres (29 mi) north-east of Bhopal, capital of Madhya Pradesh.

The Great Stupa at Sanchi is one of the oldest stone structures in India, and an important monument of Indian Architecture.[1] It was originally commissioned by the Mauryan emperor Ashoka the Great in the 3rd century BCE. Its nucleus was a simple hemispherical brick structure built over the relics of the Buddha. It was crowned by the 'chhatra', a parasol-like structure symbolising high rank, which was intended to honour and shelter the relics. The original construction work of this stupa was overseen by Ashoka, whose wife Devi was the daughter of a merchant of nearby Vidisha. Sanchi was also her birthplace as well as the venue of her and Ashoka's wedding. In the 1st century BCE, four elaborately carved toranas (ornamental gateways) and a balustrade encircling the entire structure were added. The Sanchi Stupa built during Mauryan period was made of bricks. The composite flourished until the 11th century.

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Sanchi Stupa is depicted on the reverse side of the Indian currency note of ₹200 to signify its importance to Indian cultural heritage.[4]

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The monuments at Sanchi today comprise a series of Buddhist monuments starting from the Mauryan Empire period (3rd century BCE), continuing with the Gupta Empire period (5th century CE), and ending around the 12th century CE.[5] It is probably the best preserved group of Buddhist monuments in India.[5] The oldest, and also the largest monument, is the Great Stupa also called Stupa No. 1, initially built under the Mauryans, and adorned with one of the Pillars of Ashoka.[5] During the following centuries, especially under the Shungas and the Satavahanas, the Great Stupa was enlarged and decorated with gates and railings, and smaller stupas were also built in the vicinity, especially Stupa No.2, and Stupa No.3.[5]

Simultaneously, various temple structures were also built, down to the Gupta Empire period and later. Altogether, Sanchi encompasses most of the evolutions of ancient Indian architecture and ancient Buddhist architecture in India, from the early stages of Buddhism and its first artistic expression, to the decline of the religion in the subcontinent.[5]

[References:]

1. Buddhist Art, http://www.frontline.in/archives.htm , Frontline Magazine 13–26 May 1989

4. https://www.financialexpress.com/photos/business-gallery/821450/rs-50-rs-200-rs-500-and-rs-2000-notes-images-here-are-the-new-currency-notes-released-by-rbi/lite/ , Rs 50, Rs 200, Rs 500 and Rs 2000 notes images: Here are the new currency notes released by RBI

5. Buddhist Circuit in Central India: Sanchi, Satdhara, Sonari, Andher, Travel Guide. https://books.google.com/books?id=TOrKExVXXpkC&pg=PT12 , Goodearth Publications. 2010. p. 12. ISBN 9789380262055.

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Pic of Great Stupa at Sanchi and its gateway: https://upload.wikimedia.org/wikipedia/commons/1/12/East_Gateway_-_Stupa_1_-_Sanchi_Hill_2013-02-21_4398.JPG .

Pic of Rs.200 note reverse side showing Great Stupa: https://en.wikipedia.org/wiki/File:India,_200_INR,_2018,_reverse.jpg

A couple of videos:

Sanchi Stupa, https://www.youtube.com/watch?v=ZrZtiP5_jUk , 1 min. 33 secs., published by Madhya Pradesh Tourism on 7th May 2020

ASI Bhopal Circle presents Sanchi A world heritage site in Hindi, https://www.youtube.com/watch?v=h8Y4af4G3AQ , 9 min. 33 secs., published on 5th Oct. 2016.

I hope the following will not be considered irreverent by some readers. As I was reading up and thinking of Sanchi, the song 'Kaanchi Re Kaanchi Re' of 1971 Hindi film Hare Rama Hare Krishna, unconsciously came into the forefront of my mind. The song has the phrase 'preet meri saanchi' though I don't know the exact meaning of the Hindi word, saanchi, in this context.

Here are a couple of live orchestra renditions of the song that I heard today:

Kanchi Re Kanchi Re - Rajessh Iyer & Nirupama De - GAATA RAHE MERA DIL, https://www.youtube.com/watch?v=KhMFHS7BTr0 , around 4 mins., event was in June 2018.

The audio quality of the following video could be better but even with the average audio quality, the male singer's singing is awesome: KANCHI RE KANCHI RE PREET MERI SANCHI , HARE RAMA HARE KRISHNA BY MOHIT DATTA & TUHINA (1971), https://www.youtube.com/watch?v=ht-5Zmjzvm4 , 4 min. 29 secs., published in July 2015.

The original film song starring Dev Anand and Mumtaz with singers being Kishore Kumar and Lata Mangeshkar: Kanchi Re Kanchi Re Hare Rama Hare Krishna 720p HD Song, https://www.youtube.com/watch?v=FOXkYrP3D2g , 4 min. 37 secs.

[I thank Wikipedia and have presumed that they will not have any objections to me sharing the above extract(s) from their website on this post which is freely viewable by all, and does not have any financial profit motive whatsoever.]