Examples would be the sandstorm sequences and flooding sequences as well as even in Planet Earth 1 and Blue Planet 1 they use CGI to 'enhance' the scenes with so called dozens of whales and birds, you can easily see the multiple 'blowholes' all over the place etc that is not real. The one thing I would recommend is avoiding the newer series like Africa, Blue Planet 2, Planet Earth 2 etc as they use CGI effects for a so called 'nature' show of 'observation'.
Really great series, I grew up watching the older series like Life on Earth and Living Planet so they are actually relaxing to me.
