Coriandrum sativum
Coriander likes a moist shady spot and is very easy to grow. 
The whole plant can be used, including the roots and seeds. Coriander is used in cuisines throughout the world. The leaves are rich in vitamin C. The seeds assist digestion of carbohydrates and are traditionally used in bread, cakes, stews, and meat. 
It will bolt to seed in hot weather. If it does, don't pull it out - let it seed to pop up freely in your garden next year or save the seed for use in the kitchen.
Image:
By Thamizhpparithi Maari (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons