For an honest look at today’s Germany, travelers need to venture beyond the ruined castles and cute cobbled towns. Frankfurt may be low on Old World charm, but it offers a great look at no-nonsense, modern Germany.

Ever since the early Middle Ages, people have gathered here to trade. Today, cosmopolitan Frankfurt — nicknamed “Bankfurt” — is a trading hub of a united Europe, home to the European Central Bank, and a center for global commerce.

With its trading heritage came people from around the world. You’ll notice the strikingly multi-cultural flavor of the city. A quarter of its 700,000 residents carry foreign passports. Frankfurt is often avoided by tourists who consider it just a business and transportation hub. But, with its modern energy, Frankfurt is a unique and entertaining city well worth a look.

The city, with its forest of skyscrapers perched on the banks of the Main River, has been dubbed Germany’s “Main-hattan.” While it leads the country in high-rises (mostly bank headquarters), it has plenty of people-friendly parks. In fact, Frankfurters boast that a third of their city is green space.

This park is part of a greenbelt that circles the old center and marks the site of Frankfurt’s long-gone medieval fortifications. Today that greenbelt weaves through Frankfurt’s banking district. And history hides among these trees. The Marshall Plan — that massive American aid program that helped Germany rebuild after World War II — was administered from this building.

After World War II, Germany was in ruins and its economy was in chaos. In 1948, the US gave it a complete currency transfer. It was like a blood transfusion — literally printing up the new German deutsche marks, shipping them across the Atlantic, and from here in Frankfurt, injecting them directly into the German economy.

That aid helped rebuild Germany, and it shaped Frankfurt as well. And, as if attracted to all that money, banks naturally grew up right here. The architecture is striking. By law, no German worker can be kept out of natural light for more than four hours. That’s why work environments are filled with windows. And, unlike any skyscraper I’ve been in, Germans have office towers with windows that open.

The Main Tower is open to the public and offers a breath-taking view. From its rooftop, 650 feet high, you can survey the city. With new construction nearly obliterating the river upon which the city was founded, its ever-expanding skyline exudes the vitality of the German economy.

In contrast to the glassy skyscrapers, Frankfurt’s train station is a classic. This late 19th-century glass-and-iron construction somehow survived the bombs of World War II. The building’s elegant façade dates from the Industrial Revolution, and shows the pride of that age: Atlas carries the world — but only with some heavy-duty modern help, as figures representing steam power and electricity pitch in.

Stepping inside you feel the energy of Germany’s busiest train station, where 350,000 travelers catch 1,800 trains every day.

Kaiserstrasse, a grand 19th-century boulevard, was built to connect the station and the city with style. Towering above and beyond its fine 100-year-old facades and reflecting the glaring modernity of this ever-changing city, are the skyscrapers of Frankfurt’s banking district.

Frankfurt is full of contrasts. Just a few blocks away, under those same skyscrapers, is a red light district with about 20 legal brothels — the pragmatic result of a policy of tax and regulation to take the crime out of a reality that just won’t go away.

Just a couple of blocks away there are fashionable streets lined with top-end boutiques. People-friendly pedestrian zones make it easy for both shoppers and diners. And, on a hot day, people of all ages enjoy the refreshing fountain fronting Frankfurt’s fine opera house.

The many small German-speaking states finally united into modern Germany in about 1870. Within a couple of years Frankfurt, which helped spearhead the unification movement, built this fine opera house. It celebrated both high German culture and the newly created nation.

While bombed in World War II, it was rebuilt it in the original style. Mozart, whose operas were a hit here, and the esteemed Frankfurt writer Goethe flank the entrance, reminders that this is a house of both music and theater.

Lunchtime beneath the skyscrapers can be entertaining, as herds of bankers fill countless restaurants. This street is nicknamed “Fressgass’,” roughly the “Feeding Street.”