Which tool to check multiple website availability?

I have a big list of website, something like 1000, and I would like to directly know which one is not down in order to don't waste my time by checking them one by one.

I tried to find the answer on google but it's only using with one website instead of more...

So do you know a good tools or a good script by maybe pinging the websites that I can use ?

Thank's for reading