The U66, the Bonn subway line along which each stop is colour-coded, winds from the central train station to the German environment ministry. Along the way it pops above ground, as if taking a breath of the fresh air in this impossibly green city.
Expansive university lawns and groves of trees adorn Bonn with brightly coloured leaves. Even the highways are lined with dense foliage. Fitting then that the United Nation's climate change agency is based here, along with organisations dedicated to wind power, solar energy and sustainable cities.
The environment ministry was one of the consolation prizes awarded to Bonn after German reunification, when Berlin replaced the city as the seat of the federal government.
A flurry of other non-political ministries moved to Bonn after the Berlin-Bonn Act in 1994, including the federal audit office to the federal railway authority.
Today, bank auditors, climate change negotiators and others are dispatched to Bonn for work, adding to a full-time population of students at the university.
On sunny days, many can be found stretched out on the front lawn of the campus.
Just a stroll away is the former home of Beethoven and a statue of him gazing at a church. But the highlight of Bonn is the Rhine.
Situated in a prime spot on the river just outside the city centre is the Kameha Grand, Bonn's only designer hotel. Breakfast is served under umbrellas overlooking the river.
Rooms are a masculine mix of black carpets and sharp-edged furniture, while the courtyard has whimsical oversized flowerpots growing full-size trees.
For those seeking a dose of more local culture, cafes abound in the old part of town and along the Rhine. But go early — the city closes early.