Singapore, an island city-state off southern Malaysia, is a global financial centre with a tropical climate and multicultural population. Singapore fun facts for kids. Kallang River, the longest river in Singapore, is just 10 km long.Singapore consists only of one main island and 63 other tiny islands. Most of these islands are uninhabited. The entire lyrics of the national anthem are printed in microtext on the back of the $1,000 note. Majulah Singapura (Onward Singapore) is the national anthem of Singapore.