It was in 1955 that a UK-New Zealand joint expedition first climbed Mt Kangchendzonga here. And on its 50th anniversary, the state tourism department has unveiled elaborate celebration plans, starting September 16. A commemorative stamp will be released to mark the occasion. Also members of the 1955 expedition and the first Indian expedition in 1977 will share their experiences at a function here. An I-Max laser show of the peaks, a painting and photo exhibition and cultural programmes by local artists will figure too. A book on the mountain will also be released on the occasion.