Heat olive oil in a large pot over medium heat.
Add chopped onion and sauté until translucent.
Stir in minced garlic and cook for an additional minute.
Add diced carrots and celery; cook for 5 minutes.
Mix in the zucchini and green beans; stir well.
Pour in the vegetable broth and can of diced tomatoes.
Bring the mixture to a boil, then reduce heat to low.
Season with salt and pepper to taste.
Simmer uncovered for 20 minutes, allowing flavors to meld.
Serve hot, garnished with fresh herbs.