Triveni Sangam, the meeting point of three rivers: the Ganga, the Yamuna and the invisible Sarasvati. A place where Kumbh Mela is held once in 12 years.

<a href="https://en.wikipedia.org/wiki/Kumbh_Mela" rel="nofollow">Kumbh Mela or Kumbha Mela</a> is a mass Hindu pilgrimage of faith in which Hindus gather to bathe in a sacred or holy river. In 2017 Kumbh Mela got inscribed to the UNESCO's Representative List of Intangible Cultural Heritage of Humanity.

Sand mining is said to be an environmental issue in India. Here the sand is still present but in other places there are <a href="http://www.cseindia.org/node/3878" rel="nofollow">problems with sand mining</a> .

The latest Allahabad Kumbh Mela took place in 2013 and became the largest religious gathering in the world with almost 120 million visitors. The next one is scheduled for 2025, with an Ardh Kumbh Mela ("Half Kumbh") scheduled for 2019. Every year, a smaller version of Kumbh called Magh Mela is organized which falls during the Hindu month of Magha (usually January or February). <a href="https://en.wikivoyage.org/wiki/Allahabad#Sangam" rel="nofollow">en.wikivoyage.org/wiki/Allahabad#Sangam</a> In between the place is continuously frequented by devotees.

Every year Sibirian birds appear at the holy Sangam, too <a href="https://indroyc.com/2017/11/07/siberian-birds-at-the-sangam/" rel="nofollow">indroyc.com/2017/11/07/siberian-birds-at-the-sangam/</a>