That's Three-Cornered Leek (Allium triquetrum), the triangular flower stem is diagnostic. It's originally from north Africa, but introduced all around the world, where it is generally considered a noxious weed. We have recently had several questions about it, so I researched it.

Allium triquetrum: Commonly known as Onion Weed or Three-cornered Garlic or Wild Garlic. A bulbous plant in the Onion family.

You might want to dig most of them out after they've flowered - even if you do, there'll still be some next year, its the gift that keeps on giving, even when you really don't want it to...

lol Bamboo, doesn't it just - interesting we are getting so many questions on this bulb right now.

Inevitable I suppose, MG - if it doesn't just occur naturally in the landscape, most gardens where it grows belong to people who got suckered into planting it - its often supplied in mixed collections of Alliums, with no warning about its invasive potential, but lots of flowery talk about its attractiveness.

In this case, it looks as if there were bulbs under that paving, and they've spread forward - they're too close to the paving for anything else to be the case, so probably ineradicable - controlling spread is the only option.

Sherrysgarden; if you like scallions or leeks, crop the leaves and use them instead - they're edible.

Thank you so much everyone...I had a feeling they were a weed since I couldn't find anything on them!!! Are you sure I can eat the green stems, they really do smell good and we love chives!! Thanks again. Sherry

Yes, you can eat them. Look for the ones that didn't flower yet - they taste much better.

Just like Chives, you can eat the flowers as well as the stems - you'll probably find the flowered stems a bit tough (like Chives get), but the leaves remain softer and edible - cropping the plant is another form of useful control as well. http://eatlikeagirl.com/edible-wild-flowers-three-cornered-leekwild-onion/