A secret lake, natural steam chambers and a grotto once described as the eighth wonder of the world. Grotta Giusti in Tuscany is no ordinary spa. The five-star resort has just been named the World’s Best Thermal Grotto Spa at the 2026 World Spa Awards, taking home the title for the tenth consecutive year.

Here are five reasons this remarkable Italian retreat deserves a place on your travel wish list.

1. Descend into Europe’s Largest Natural Thermal Grotto

Hidden directly beneath the hotel is an extraordinary underground world stretching more than 200 metres. Discovered in 1849, the natural grotto is divided into three atmospheric chambers named Paradise, Purgatory and Hell.

Each chamber offers a different experience, with temperatures ranging from 28°C to 34°C. With humidity reaching 98%, the caves create a natural steam bath unlike anything you might find in a conventional hotel spa.

2. Float in a Secret Underground Lake

Deep inside the grotto lies a natural thermal lake, where guests can enjoy guided floating sessions surrounded by ancient rock formations.

For something a little different, there’s Piloga, a combination of Pilates and yoga practised in this extraordinary underground setting. More adventurous visitors can explore the possibility of thermal cave diving.

It’s an opportunity to experience the natural environment of the grotto in ways that go far beyond an ordinary spa treatment.

3. Experience a Spa Once Praised by Giuseppe Verdi

Grotta Giusti has been attracting attention for nearly two centuries. The celebrated Italian composer Giuseppe Verdi reportedly described its remarkable underground caves as the eighth wonder of the world.

The resort itself occupies the former 19th-century residence of Italian poet Giuseppe Giusti. Today, this historic property combines its literary heritage with five-star accommodation and contemporary spa experiences.

4. Discover the Appeal of Natural Thermal Wellness

Forget artificial steam rooms. Grotta Giusti’s naturally heated, mineral-rich steam creates a distinctive wellness experience beneath the Tuscan countryside.

The resort promotes its thermal environment for relaxation, respiratory wellness and its potential anti-inflammatory benefits. Visitors can move between the different chambers, experiencing the changing temperatures while enjoying the unusual surroundings of the cave.

It’s a setting where geology, history and modern wellness come together.

5. Visit a Spa That Has Won the Same Global Award Ten Years Running

Winning an international spa award is an achievement. Receiving the same title for ten consecutive years is particularly noteworthy.

At the 2026 World Spa Awards, Grotta Giusti was once again recognised as the World’s Best Thermal Grotto Spa, continuing a decade of recognition for its unique underground attraction.

Part of the Italian Hospitality Collection, the resort offers visitors the opportunity to combine a Tuscan holiday with a distinctive thermal experience.

Whether you’re planning a romantic escape, a wellness retreat or a luxury holiday in Italy, Grotta Giusti offers something considerably more unusual than a conventional spa break.

Plan Your Visit

Grotta Giusti Thermal Spa Resort

Monsummano Terme, Tuscany, Italy

World’s Best Thermal Grotto Spa 2026

Natural thermal grotto, guided floating and wellness experiences

Explore Grotta Giusti