SLIDESHOW: World's Tallest Service Dog Visits Minn. Kids
A very big guest made a special appearance at Children's Hospital in Minneapolis.
'Bentley' is the world's largest service dog.
The Great Dane measures over four feet tall when standing on all fours.
Bentley's owners started training him to go into hospitals when their son Chase was diagnosed with an aggressive form of bone cancer.
Now Chase is better, and Bentley tours the country visiting kids in hospitals.