An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
a. An example of a vista space. Here, all landmarks are visible from a single viewpoint. b. An example of an environmental space. Here, navigation is required to view and encode all the landmarks.