Topsy is a search engine that includes websites, photos and videos (as Google does), but it also includes Twitter. If you’re looking for what people are tweeting about a certain topic, you can of course use Twitter’s search box, but with Topsy, you can do all your searches together at the same time.
For example, if you search for “tokyo 2020 olympics”, you can see how many tweets there’ve been in the past 30 days (or 12, 7, 1 day, past hour, all time, or, very usefully a specific range in time) and you can see those tweets, as well as articles from news sources, videos, and photos. There’s a pro account, too, but for what my students need, the free site (no log in necessary) provides plenty. All in all, a great search engine to add to your language learning and research toolbox.