For the first five seasons, Ross works at the Museum of Natural History. He is one of the paleontologists there. He soon gets his own office in Season 3. In The One With Phoebe's Uterus, it's shown that Joey also works here, as a tour guide. In The One With Ross' Sandwich, Ross goes on sabbatical because he becomes angry with his boss when he eats Ross' sandwich. However, when Ross' boss visits him to ask him to come back to work at the museum feeling that Ross has controlled his anger, Ross just discovers that Monica and Chandler are in a relationship and he gets mad again, for which he gets fired.