Want to see London as plain as the nose on your face and not pay money for it? Go to Sky Garden, which offers a 360-degree panorama to all sides. This is the highest garden in London.
If you cannot find which of the high-rises the garden is in, ask the locals where "Walkie-talkie" (the shape of the building looks very much like a walkie-talkie), and then you can easily find the right building, and in a few minutes you will be able to enjoy the view of the capital.
The entrance is completely free of charge.
Working hours:
Mon - Fri: 10 - 18
Sat - Sun: 11 - 21
By the way, do not forget that London refused entrance fees to its largest museums, so you can visit the National Gallery, the British Museum, the Tate Modern Art Gallery, the National Portrait Gallery and many others also for free.