In Spanish there are two letters that are not very common. They are w and gü and they both sound similar as in the word "water". The letters "gü" are only used with the vowels "e, i". Let's see a few examples to show their similarity. There are not many:

w
Ellos juegan waterpolo.
     They play waterpolo.
Ella bebe whisky.
     She drinks whiskey.
Ese sitio web.
     That website.
¿Quieres un sándwich?
     Do you want a sandwich?
Mire qué lindo este bungalow.
     Look how cute this bungalow.

gü
El desagüe está tapado.
     The drain is clogged.
Soy nicaragüense.
     I'm Nicaraguan.
La cigüeña trae a los bebés.
     The stork brings the babies.
Aplícate ese ungüento.
     Apply this ointment.
Los pingüinos son amigables.
     Penguins are friendly.