This big plaque was seen on the walls of the Victoria Theatre.
I guess it is there because Victoria Theatre was the venue for the first public performance of "Majulah Singapura" on 6 September 1958. [from Wikipedia]
What is Majulah Singapura? It's the National Anthem of Singapore. Translated to English, it means Onward Singapore.
To listen to the anthem, you can visit Singapore InfoMap at: www.sg