In a large pot, heat oil over medium high heat. Saute the carrots, celery and onion for a few minutes. Add garlic and herbs. Cook for a minute or two longer. Add the greens, the tomato puree, salt and pepper and red pepper flakes and 6 cups of water or vegetable stock. Cook for 20-30 minutes and adjust seasoning to taste. Tear bread and add to soup, stir for a few minutes until it is absorbed. Serve with a drizzle of olive oil and enjoy.