"The tallest building" vs "The highest building"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hi

Are the following the same?

I would love the know the difference if any.

Tom

2

.
No difference here. ‘Tall’ tends to refer to objects with relatively small bases, that is all.
.

3

Actually the terms are quite different. “Highest” refers to the overall height of the building including the height of whatever it is built on, and “tallest” is just the dimension of the buildling itself. So a three meter tall building in Katmandu is higher than the Petronas towers which are 400m tall but are built at sea level.

Another example: Mt. Everest is the highest mountain, the summit of which is at 8848m but many claim Mauna Kea is taller because the mountain starts way below sea-level and rises 10,200m to its summit.