I did a quick search of "safe websites for children" and here are the results:
https://www.google.ca/search?q=safe+websites+for+children&rlz=1C1VSNC_enCA647CA647&oq=safe+websites+for+children&aqs=chrome..69i57.6306j0j8&sourceid=chrome&ie=UTF-8
I also searched "keeping your child safe on the internet" and here are the results:
https://www.google.ca/search?rlz=1C1VSNC_enCA647CA647&ei=6tG6WobxJ9PejwPznaewDA&q=keeping+your+child+safe+on+the+internet&oq=how+to+prevent+children+from+seeing+unsafe+websites&gs_l=psy-ab.1.3.0i71k1l6.0.0.0.23762.0.0.0.0.0.0.0.0..0.0....0...1..64.psy-ab..0.0.0....0.bB6GuL97eTU