Concatenating a list of data.tables

A list of data.tables has been loaded into your R session: gdp. Its elements contain a data.table for each continent, each data.table containing the gross domestic product (gdp) in the year 2000 for the countries in each continent (data sourced from the Gapminder foundation). Your goal is to build a new data.table containing the observations from all data.tables in the gdp list