The slabs weigh from 13 to 17.8 tons each.
The tradition at the 9/11 Memorial draws hundreds to lower Manhattan for reflection.
Nearly 3,000 people died in the terror attacks on Sept. 11, 2001.
"The last time I was here, the towers were coming down."
The World Trade Center isn't the only place in the city that honors the victims.
Degraded genetic material once deemed unusable may be salvaged with new technique.
More than 7 million daffodil bulbs have been planted across NYC since 2001.
New Yorkers can honor 9/11 victims and improve their community at the same time.
There are several events in the city that don't require you to go downtown.
The diet is high in olive oil and fish, and low in red meat.