One of the biggest landmarks in Vienna is the Schönbrunn Palace. The palace is located in the western part of Vienna and accessible via U4 Ubahn (map). Millions of people visit it every year. You can tour the inside of the Palace, unfortunately you can not see all of the 1400+ rooms. However, you can get a pretty good picture of the Emperor’s apartments for his summer residence.
Once you finished the tour, you can enjoy the vast Schönbrunn Gardens. There are many different gardens that are sprinkled throughout the property. Most people head over to the Gloriette, to enjoy a beautiful view of the city and the Schönbrunn Palace.
If you want to continue exploring the gardens you will probably stumble on the oldest Zoo in Europe. The Zoo is adjacent to the gardens. In rather close proximity to the Zoo, there is another beautiful structure the Palmenhaus. Built around 1881/1882, the current green house holds three different pavilions with three different climate zones: a cold house in the north, a temperate in the middle and the tropical house in the south.