More than 100 children from around the world joined in song on the Kennedy Center Concert Hall stage last week, during the culmination of the International Children's Choir Festival.

But for the young musicians -- from Puerto Rico, Hong Kong, People's Republic of China and Thailand -- the excitement of their visit extended beyond the concert hall and into the city that differs so markedly from their home cities.

"Everything is so much more colorful on the streets here," said Jiang Zhu, a 16-year-old singer from Beijing.

The groups from Bangkok and Beijing carry the special duty of representing two of Washington's three sister cities. On one sightseeing excursion, the singers from Beijing were particularly pleased to see the ornate arch at Seventh and H streets NW that was given to the District by the People's Republic of China as a token of friendship.

The festival is the second gathering of the International Society of Children's Choral and Performing Arts, which was founded by its chairman, Dr. Yip Wai-Hong.

The itinerary for the festival, from Aug. 8 through 12, would have exhausted most seasoned musicians. But the never-tiring children, aged 6 to 17, happily rose at 6:30 a.m. and proceeded from sightseeing and performances around the city, to rehearsals and performances at the Kennedy Center. Their days usually ended about 11 p.m.

Last Tuesday and Thursday, concerts were given by the Bangkok Children's Choir, the Chorus of the China National Children's Centre in Beijing, the San Juan Children's Choir and Yip's Children's Choir from Hong Kong.

The four groups come from a larger membership of 17 ensembles from 14 countries. All of the groups perform their native folk music, as well as music from the western classical tradition.

One selection included in the festival was a short piece performed by the Bangkok group titled "Love at Sundown," written by the king of Thailand, who is considered an accomplished musician.