People enjoy jazz during Bohemia JazzFest 2019 at the Old Town Square in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)

American multi-instrumentalist Ralph Towner plays the guitar at Bohemia JazzFest 2019 in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)

American multi-instrumentalist Ralph Towner plays the guitar at Bohemia JazzFest 2019 in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)

People enjoy jazz during Bohemia JazzFest 2019 at the Old Town Square in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)

People enjoy jazz during Bohemia JazzFest 2019 at the Old Town Square in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)

Musicians perform during Bohemia JazzFest 2019 in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)

Rudy Linka, founder and director of the Bohemia JazzFest, launches this year's festival in Prague, the Czech Republic, July 8, 2019. Bohemia JazzFest 2019, one of the largest summer music festivals in Europe, opened here on Monday. The festival will last till July 15, featuring headline performers from all over the world playing in cities including Prague, Pilsen and Buro. (Xinhua/Dana Kesnerova)