Here is a great post with some tips on how to find files within your Google Drive: https://www.labnol.org/internet/google-drive-search-tips/29508/
Find free-to-use images in Google: https://support.google.com/websearch/answer/29508?hl=en&ref_topic=3081620
Some great ways to refine your web searches on Google here: https://support.google.com/websearch/answer/2466433
Here are some great sites for virtual field trips.
The Hidden Worlds of the National Parks