Krista and Tatiana Hogan are conjoined twins joined at the head. But unlike all other known craniopagus twins the Hogans’ brains are also linked, by a small bridge connected the thalamus of one girl to the thalamus of the other. Susan Dominus wrote for The New York Times last year:

Suddenly the girls sat up again, with renewed energy, and Krista reached for a cup with a straw in the corner of the crib. “I am drinking really, really, really, really fast,” she announced and started to power-slurp her juice, her face screwed up with the effort. Tatiana was, as always, sitting beside her but not looking at her, and suddenly her eyes went wide. She put her hand right below her sternum, and then she uttered one small word that suggested a world of possibility: “Whoa!”

New York Times Magazine: Could Conjoined Twins Share a Mind?

(Thanks Trevor)