K.V. is the general name for the cafe, bar, restaurant and meyhane in the narrow passage at tunnel square. They're not all in one place but next to each other so you can choose one you like.
I like the old style decoration of cafe and mostly quietness being away from crowd of Istiklal. You may enjoy a cup of coffee, desserts, light food or lunch all day long and bar, restaurant or meyhane at night. Live jazz music is also available on some days. A good choice for hot summer days as outsie is always chilly. Tunnel is the last point of Istiklal str., so you may rest here and enjoy a drink. K.V. is at the opposite of Tunnel entrance, you may notice easily. On Map: