A viewing deck was installed by the National Museum in 1997. The site was closed for 14 months until October 2015 for renovations and the installation of a newer viewing deck. Graffiti by visitors is a problem. And though the site provides "visitor books" for guests to draw upon, these are rarely used as they are safeguarded by the National Museum staff. The tunnel leading to the area is not monitored and is also the site for graffiti by visitors, though these may have a positive impact as it channels away graffiti from the main site.