Salt mine therapy

Boys play basketball in the facilities of Belarus' Republican Clinic of Speleotherapy within a salt mine, as part of their treatment, near the town of Soligorsk, south of Minsk, February 19, 2015. According to the state clinic, more than 7,000 children and adults seek medical treatment for respiratory illness each year in the subsurface chambers of its facilities, located 420 meters underground between layers of potassium and stone.

Children and their teachers wait before descending into the facilities, February 19, 2015. The clinic treats bronchial asthma, chronic obstructive pulmonary disease, chronic bronchitis, hay fever, allergies and other respiratory conditions, according to the clinic's website. It also says patients recover by breathing in "curative light ions" in the mine's stone salt caves, as well as through electrotherapy, phototherapy, massage,.

A girl reads a book while resting in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children walk in the facilities underground, February 19, 2015. REUTERS/Vasily Fedosenko

A child looks on upon returning to the surface with others after spending time at the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

A teacher exercises in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children rest in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children play table tennis in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children walk in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

A boy exercises in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children rest in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children play in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Youths spend time in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children play billiards in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Youths chat amongst themselves as workers walk past in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

Children with doctors from the clinic descend into a salt mine, February 19, 2015. REUTERS/Vasily Fedosenko

Workers change a lamp in the facilities, February 19, 2015. REUTERS/Vasily Fedosenko

A nurse of Belarus' Republican Clinic of Speleotherapy speaks on the phone, February 19, 2015. REUTERS/Vasily Fedosenko