We use TreeMap Charts for demonstrating the hierarchical data. They usually look like a table with cells of different width and height. TreeMap Charts remind of Heat Map Charts, but the last ones cannot process the data which items are somehow ranked by the level.
This Chart demonstrates 1000 best companies in 25 industries. The highest level demonstrate the cells representing industries, and the cells representing companies are slightly visible through them, so the industries' cells are colored due to their companies' revenue. Labels show the name of the industry, and the tooltips show the whole revenue that was earned by all companies in this industry. By clicking the industry cell the next level will open and demonstrate the companies belong to the chosen industry. All cells are colored according to the revenue they got. Labels demonstrate only the company name and the tooltips show the revenue and the city where this company is placed.