The small village of Capel Celyn, in the Tryweryn valley, has become visible for the first time in decades following the heatwave.
On 21 October, 1965, the village disappeared under 70 billion litres of water.
The 67 residents were forced to move out after Parliament passed a law allowing Liverpool to flood the valley including a school, chapel and 12 farms to create a new water supply.
It made the community homeless.
Cllr Mabon ap Gwynfor visited the village and discovered the remains had become visible because of the recent hot weather.
The events of Tryweryn were said to awaken the nationalist cause for a generation of people in Wales.
Former Plaid Cymru leader Lord Dafydd Wigley said it made Wales realise it needed its own parliament to ensure it would never happen again.