Is this the most magical swimming pool in the world? The 'big hole' hidden in a grotto on a volcanic island

• The mesmerising pool, almost 100ft down, is on the volcanic island of Upolu in Samoa
• Visitors can enjoy crystal-clear waters populated with tropical fish and a sandy bed
• A steep ladder leads down to the water, with tourists using it to dive into the pool 

 This natural swimming pool on a volcanic Samoan island offers visitors the ultimate experience in relaxation.To Sua Ocean Trench, which literally translates as 'big hole,' is located in Lotofaga village, on the south coast of Upolu island in Samoa. When the volcanoes erupted on the island, much of the ground fell away, and this 98-foot deep hole was the result.Steps lead down to a ladder, which tourists can use to descend into the grotto, or use as an impromptu diving board (providing the water levels are high enough).For those less brave, a tumble in from a board a matter of inches above the water may be the safer option.

 The green landscape is matched by crystal clear waters, an abundance of tropical fish and a sandy bed. A series of canals leading from the pool to the South Pacific Ocean ensure the hole is never dried out.In order to protect the serene spot, as well as maintain the safety of the visitor routes into the water, there is a charge to swim. It will cost adults £10 ($15), children £3.85 ($6.00), but is free to those under the age of seven.

 Visitors to the trench are warned to take care when walking down the ladder, as expectedly, it can become slippery. CJB1985 adds on TripAdvisor: 'The climb down looks bad but if you take your time and wear sandals it's ok.'The review website has scored To Sua Ocean Trench a four-and-a-half rating out of five based on visitors' reviews. Of the 401 people to have commented on the tourist attraction, 319 have rated it as 'excellent.'