The Singapore Changi Airport commemorative coin was issued on 7 December 1981 to commemorate official opening of the Singapore Changi Airport. I have a uncirculated Cupro-Nickel coin having a face value of $5, and which was issued at $6 with a mintage of 220000.
On the coin, you can see the iconic control tower, Terminal 1 and its carpark, along with several planes lined up and one flying away from the airport. The other side says "Singapore Changi Airport 1981". Definitely a very sentimental coin to keep.