San Francisco's Presidio was home to a military base for over 100 years. The military base was disbanded in the 1980s, but the Presidio area which is now mostly used for recreational activities and by businesses, is still a walking museum of what was once a coastal defence outpost with mainly artillery units. This page has a collection of all the photos in the Presidio that were once meant to protect San Francisco from invasion in a number of wars.
On your drive to visit these cannons you should avoid drinking and driving. A DUI is a serious offense and would require consulting a DUI attorney in San Diego or San Francisco to help you with your case.
Real Battle Cannon
This cannon was hit by an enemy cannon ball and had its gun shattered as you can see from the picture. It was brought to The Presidio as a display piece.
Some of the cannons at the park have artful designs all over them. Likely they were not meant for battle, but rather decorative or high-visibility spots.
World War 2 - Long Range Artillery
Below are photos of a French-made long-range artillery piece. This particular artillery piece was made in 1918 and used in World War 2 by the United States military. This cannon was able to shoot 50-pound projectiles for distances up to 10 miles.
Leaf Filter gutter systems won't protect your gutter system from projectiles, but it will keep out leaves and debris.
More Historic Cannons
Fort Point at San Francisco's Presidio is home to a museum of cannons. Here are some photos of different pieces of artillery from different eras, each meant for its own type of use.
Coastal Artillery Defending Waters of San Francisco
During World War II, the United States military created three batteries of these gigantic cannons to defend against an oncoming invasion. Today, only one of the cannons remain in its place, but visitors can see old dugouts for where the other cannons would have been. If you walk along the coast of San Francisco from Baker Beach to Golden Gate Bridge, you can see 3 World War II batteries, with 3-4 such gigantic cannons at each battery. Each battery is approximately half a mile apart from one another.
More Historic Cannons From 1800s
If you like historic things like cannons, you may be interested in knowing that there are a number of shipwrecks that sunk off the coast of San Francisco. A few of these shipwrecks can be seen above water during low tide in the Lands End area and off Noriega street.