Buenos Aires 
in $630s RT
JakeJFC
You'll want to pack your dancing shoes for Buenos Aires - it's the birthplace of tango, after all!
But you'll need a walking pair too, especially if you want to poke around the city's hidden underground tunnels.
What's that? You didn't know about the vast subterranean network of tunnels built under Buenos Aires in the 1600s for reasons that remain unknown to this day? Guess you're in for a treat, then!
The main access point to the tunnels is under the Manzana de las Luces ("Block of Lights") in central BA, a religious complex initially built by Jesuit missionaries. Check out the church of San Ignacio and the cloisters before taking a guided tour of the mysterious realm below.
Alternatively, the museum of El Zanjón de Granados in San Telmo also offers visitors a look below the city streets, along with a tunnel-related history lesson.
Jack's take
This may be your last chance to grab non-stop flights to Argentina for this year at a reasonable price. The spring trips may go lower in a few months' time, but if you don't want to risk waiting for a sale, these are solid!