Cave. Earth Russia mission 5, kill the hive which re spawn there. Farm it in 1 hour blocks Lots of green and blues and you'll get legendary engrams. Fastest way to lvl up your class and cryptark rank at the same time too. You'll also get public events every 30 minutes for the legendary materials. Motes of light, ascendant material/ shards to upgrade your gear. It's boring as hell, but it's the best way to get the weapons and gear if you don't want to smash your head a against a brick wall and spend huge amounts of time running strikes for little reward.