It's not every day a song sung primarily in Spanish goes to #1 in the US. It's not even every decade. But "Despacito," a collaboration between Puerto Rican stars Luis Fonsi and Daddy Yankee, has done it with a late-breaking assist from Canadian pop idol Justin Bieber. The Bieber-featuring "Despacito" remix, you may have heard, is the first predominantly Spanish-language single to hit #1 in this country since Los Del Rio's "Macarena (Bayside Boys Mix)" ruled the summer of 1996. It's a lot better than "Macarena," too -- lithe and airy yet hard-hitting in a way that's ideal for the hot summer nights that are about to unfold. The track is now by far the biggest hit ever for both Fonsi and Daddy Yankee. And considering it just logged a second week at #1, and that we are on the brink of Memorial Day weekend, it doesn't appear to be going away any time soon.