Berlin Botanical Garden and Botanical Museum

The Berlin Botanical Garden is about 126 acres, making it one of the world's largest botanical gardens, and it has approximately 22,000 types of plants. In the 39-acre plant-geography section, you can see plants from all over the northern hemisphere. There is also a 42-acre Arboretum and taxonomy section where you can learn about woody and herbaceous plants. The greenhouse complex consists of 16 houses where visitors can wander through tropical and subtropical vegetation.
In the botanical museum, you can see enlarged scale models of structures that are normally too small to be seen by the naked eye. There are also sections where you can view entire habitats through glass. The museum also has plants on display all year that can only be seen for a few weeks or even a single day in the garden. There is also a library of botanical books in the museum.
The Berlin Botanical Garden and Museum is a great place to learn about plants from all around the world, but it's also an escape from the noise and bustle of the city. It's also a nice place to escape the cold if you're visiting during the winter. 

Practical Info

The Berlin Botanical Garden and Museum is located at Königin-Luise-Straße 6-8. The museum is open daily from 10am to 6pm. The garden opens daily at 9am and closes between 4pm and 9pm depending on the time of year.