Price drop due to the release of the Segwit2X beta. Next critical date is the 14th, when miners start running it as their main node. On the 21st they begin signaling, and if this is successful the Segwit system is locked in after 3 days.

Should the Segwit2X signaling fail, then on August 1st BIP148 will come into effect, and Segwit will be enforced on the Bitcoin network, which may lead to a chainsplit. I recommend people hold their Bitcoin in their own wallets during that volatile period of time.