Only In France 12 - Iceberg in the Street

An iceberg, weighing nearly 20,000 kilograms and cut from Europe's largest glacier, was placed on a pavement to attract passersby to an Iceland exhibition. This ancient iceberg, aged between 1000 and 2000 years, was displayed outside the Palais de la de Convert in Paris two weeks after being cut. It served as a striking example of the exhibition, symbolizing the tip of the iceberg.

What was the purpose of placing the iceberg on the pavement?

What does the phrase 'the tip of the iceberg' imply in the context of the exhibition?