The Mein River is a tributary on the right bank of the Rhine River in Germany. Frankfurt is one of the best cities to visit the River Maine. It is one of the world's financial centers. Frankfurt's history can be traced back to B.C. In World War II, 33 bombings destroyed 80 [% of Frankfurt's buildings. Thousands of years old city, into a ruin. After World War II, Frankfurt rebuilt rapidly and developed amazingly. Today, besides chemistry, electronics and machinery industry, the tertiary industry such as transportation, finance and exposition is flourishing. As soon as the city changed its old outlook, there were many tall buildings, and Frankfurt became an internationally renowned metropolis.