New York Today: Extreme Drop

By ANNIE CORREAL and ANDY NEWMAN

Timothy Clary/Agence France-Presse — Getty Images

Not this again.

What you need to know for Thursday: a return to winter temperatures, and the aftermath of a deadly building collapse.

At Least 7 Killed as Gas Explosion Hits East Harlem

By MARC SANTORA

A large explosion caused by a gas leak destroyed two buildings in East Harlem on Wednesday, killing at least seven people and injuring at least two dozen more.

• Video: Scenes From the Building Collapse

East Harlem Explosion ‘Ripped the Stomach Right Out of You’

By COREY KILGANNON and SARAH MASLIN NIR

The building collapse in Harlem instantaneously trapped people in rubble and just as quickly sent residents into the street to help.

For Friends and Relatives of the Missing, Shock, Questions and, Most of All, Fear

By N. R. KLEINFIELD and NIKITA STEWART

After an explosion in East Harlem, relatives of missing people were making phone calls and checking hospitals, trying to keep hope alive.

Standing for More Than a Century, Only to Vanish in an Instant

By NIKITA STEWART

The two buildings that were wiped out by an explosion had been fixtures on their block in East Harlem since 1910.

Smelling a Problem at the Site of the East Harlem Explosion

By PATRICK McGEEHAN

The only sign of trouble that Consolidated Edison received before the explosion in East Harlem on Wednesday was a call from a customer on upper Park Avenue who had been smelling gas since Tuesday night.

City Room

Metro-North Service Restored After Explosion in Harlem

By MATT FLEGENHEIMER

The Metropolitan Transportation Authority said some of Metro-North Railroad’s New Haven and Harlem line service into and out of Grand Central Terminal would be restored after it was suspended earlier.

Ozier Muhammad/The New York Times

A teacher, Joanne Perrina, left, and a teaching coach, Emily Hamlin, working with students on a counting exercise.

A Study Seeks to Determine What Makes Prekindergarten Successful

By KATE TAYLOR

The study will follow 4,000 children to see if curriculum can create lasting improvement in students’ skills and a likelihood to persevere academically.

Interactions of Bin Laden and Son-in-Law Detailed in an F.B.I. Document

By BENJAMIN WEISER

Lawyers for Sulaiman Abu Ghaith, who is on trial on terrorism charges, sought permission from a judge to present the document, a full summary of his interrogation, to the jury.

Albany County Orders a Halt to Growth in Oil Processing

By JAD MOUAWAD

Citing the potential impact on public health, a moratorium was ordered on the expansion of oil processing facilities at the Port of Albany.

Hip-Hop Pioneers Plan a Museum for the Bronx

By WINNIE HU

Some of the elders of the genre want to underscore its Bronx roots by opening a museum — to be called the Universal Hip Hop Museum — inside the Kingsbridge Armory.