We test a method for visualizing and measuring enterprise application architectures. The method was designed and previously used to reveal the hidden internal architectural structure of software applications. The focus of this paper is to test if it can also uncover new facts about the applications and their relationships in an enterprise architecture, i.e., if the method can reveal the hidden external structure between software applications. Our test uses data from a large international telecom company. In total, we analyzed 103 applications and 243 dependencies. Results show that the enterprise application structure can be classified as a core-periphery architecture with a propagation cost of 25%, core size of 34%, and architecture flow through of 64%. These findings suggest that the method could be effective in uncovering the hidden structure of an enterprise application architecture.