I have to agree with lanhua about the Singapore Botanic Gardens. There are two other Botanic Gardens of note in South-East Asia.; the Penang Botanic Gardens in Penang, Malaysia; and the Bogor Botanic Gardens near Jakarta, Indonesia. But for sheer beauty and the extensive orchid collection the Singapore Botanic Gardens tops them all. The Botanic Gardens was a pioneer in orchid hybridising in Asia and is still a leader in the field.
Thanks lanhua for the superb photos. They brought back so many happy memories of the times spent there.