You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "how long is the us border with mexico?" whose answer is 1,989 mi.
Each document should contain about 30 words, and these documents should contain useful information.

Query: length of us border with mexico
Useful Output:

Doc 1: The international land border between the United States and Canada is the longest in the world at almost 8,900 kilometers.
Doc 2: The Mexico–United States border — 2,000 miles of terrain ranging from desert to urban sprawl — is the most traversed border in the world
Doc 3: The US/Mexico border spans about 2,000 miles, across four states (Arizona, New Mexico, California and Texas) and an incredibly diverse array of biomes ranging
Doc 4: The entire U.S.-Mexico border is about 1,950 miles long (it's hard to measure exactly over all of the Rio Grande's twists and turns). So today,
Doc 5: The border between the United States and Mexico stretches for nearly 2,000 miles from the Gulf of Mexico to the Pacific Ocean and touches