duckduckgo is mainly a meta search engine (relies on search API of Yahoo that relies itself on Bing, Yandex, etc.). Plus it shows some related snippets from Wikipedia and other data-sources.

Several well known web search engines are now defunct or switched to meta-search business (like Yahoo with Bing data).

There are only a few international/world-wide search engines with a crawler:

Google, Bing, Yandex, Baidu, Gigablast, (Archive.org/Wayback Machine)