Crews prepare for the rise of balloons into the sky at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)

Balloons rise into the sky at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)

Balloons rise into the sky at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)

Balloons rise into the sky at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)

Crews prepare for the rise of balloons at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)

Balloons rise into the sky at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)

A balloon rises into the sky at the Bristol International Balloon Fiesta at Ashton Court, Bristol, Great Britain on Aug. 6, 2015. (Xinhua/Han Yan)