People enjoy an outdoor concert at Palm Garden in Frankfurt, Germany, August 1, 2020. A series of concerts are held here from August 1 to 30 with strict COVID-19 control and prevention measures. (Xinhua/Lu Yang)

Some seats are taped to ensure social distancing during an outdoor concert at Palm Garden in Frankfurt, Germany, August 1, 2020. A series of concerts are held here from August 1 to 30 with strict COVID-19 control and prevention measures. (Xinhua/Lu Yang)

Artists perform during an outdoor concert at Palm Garden in Frankfurt, Germany, August 1, 2020. A series of concerts are held here from August 1 to 30 with strict COVID-19 control and prevention measures. (Xinhua/Lu Yang)

Artists perform during an outdoor concert at Palm Garden in Frankfurt, Germany, August 1, 2020. A series of concerts are held here from August 1 to 30 with strict COVID-19 control and prevention measures. (Xinhua/Lu Yang)