Two decades ago, when the Twin Towers were attacked on September 11, 2001, Lower Manhattan would be forever altered. Not only did an iconic piece of the skyline disappear, taking with it almost 3,000 lives, the demolition, rebuilding, and reshaping of the site has been in progress for seventeen years. Along the way, new buildings opened – 1 WTC3 WTC4 WTC, the Santiago Calatrava-designed transportation hub (aka the Oculus), and others. The 9/11 Memorial & Museum opened, and new streets were run through the former super block, along the same paths they once took before the Twin Towers were built. A new elevated park was built and the Cortlandt Street subway station re-opened just this past Saturday. A new performing arts center is on the way and after financial troubles, the new St. Nicholas Orthodox Church is back on track.

Despite the steady, yet drawn-out construction that has made the World Trade Center what it is today, there are many remnants that can be located on the same 16-acre site. It’s the 20th anniversary of the 9/11 attacks on the World Trade Center but if public commemoration is less your thing, use this guide to spend today or any day to note the reminders of what once was here.

1. Twin Tower Tridents

These two 70-foot tridents from the South Tower that were once enveloped in aluminum. After the World Trade Center attacks, they were catalogued and stored with other artifacts in the hangar at JFK Airport, and then brought back to the site to be placed in the entrance pavilion of the 9/11 Museum. By September 2013, the tridents were already in the space, although the museum did not open until May 2014. According to the 9/11 Memorial & Museum, each trident weights 52 tons.