Meiji Jingu (明治神宮), located in Tokyo proper, is a huge Shinto shrine dedicated to Emperor Meiji (1852-1912) and his wife Empress Shoken (1849-1914). It is one of the most prestigious Shinto shrine in Japan. (For details about this shrine, see the article on Meiji Shrine.)
In early January, a custom called hatsumode (初詣) is practiced throughout Japan. In this custom, people visit Shinto shrines (and some major Buddhist temples) to offer their first prayers of the year. And of all the shrines and temples in Japan, Meiji Shrine attracts prayer-offerers the most - it's estimated that over three million people visit this shrine during the first three days of January.
Usually, Meiji Shrine is open from 6:40am to 6:00pm at this time of the year, but it will not be closed from 6:40am of New Year's Eve to 7pm of New Year's Day, and trains will also be running meanwhile.
Described below is what it's like to visit Meiji Shrine at 4am on New Year's Day. The shrine will be very crowded on this day, but around 4am is probably the least crowded hours of the day.

Meiji Shrine at 4am on Jan 1

There are three entrances to Meiji Shrine, and the south entrance is the main approach.

Stalls are set up along Omotesando Street, which is the other side of the JR Yamanote Line from the shrine.

Foods and survenirs are sold at this corner.

The South shinmon gate is decorated with New Year's ornaments.

The space to through in money when making wishes was created in front of the Outer Haiden.

Outside the east entrance to the courtyard, stalls to sell amulets were set up.

Fires were placed along the north approach to the shrine.

Hatsumode in the daytime

Generally speaking, the first three days of a new year is considered to be best suitable for the Hatsumode. The number of visitors is smaller in the morning than in the afternoon.