War memorial sites tend to be very scenic. As such, one tends to feel the desire to take photos there. Furthermore, the war memorial sites tend to be key landmarks in the cities/towns they are located. Therefore, if you take photos with the war memorial site as a background, that would serve as ‘evidence’ that you visited the city/town in question.
In most cases, the people who manage war memorial sites have no problem with photos being taken there. You are therefore not likely to encounter any undue resistance, if you want to take photos at a war memorial site. It is nonetheless still a good idea to check with the people who manage the specific war memorial site you are visiting. So this would just be a question of asking them whether they are okay with you taking photos at their site.
While taking photos at a war memorial site, you need to be considerate about other people who may be visiting the site at the same time with you. You need to avoid misunderstandings: like where the people get the impression that you are photographing them.
If you can get a camera without the ‘flash’ feature, that would be an even better idea. Cameras with the ‘flash’ feature can be very distracting to other people who may not be interested in your photography.
It would be a good idea to take just a few photos, within just a few minutes. The idea here is to avoid being a distraction to other people who may be visiting the war memorial site at the same time as you.
Finally, having been allowed to take photos at the war memorial site, you need to thank the people who manage the site (on your way out). This is a question of according them gratitude for having granted you the favor of taking photos at their war memorial site. You need to remember that they had the option of denying you the opportunity to take photos at that particular war memorial site.