Jasper Winters's millhouse

Millhouse located in Atlanta and previously owned by Jasper Winters is also a base of operations for John Constantine's team.

Under Jasper Winters
At some point in time Jasper Winters purchased the millhouse in Atlanta to keep an eye of his daugther Liv Aberdine and storage assorted magical artifacts he acquired through his lifetime. The house was also used for Winters's practices of cartography and divination.

Under John Constantine
John Constantine made a promise to Winters that he will give the keyes to the millhouse to Liv after his death. In 2014, shortly after Jasper indeed died, John escorted Liv, now chased by demon Furcifer to a millhouse, to keep her safe. After demon was deafeated Liv decided to leave property for Constantine and Chas Chandler to fight the Rising Darkness, among with the map she made using her divination powers.

Soon after Zed Martin moved from Heddwich to Atlanta to join the team, after Constantine went to Heddwich to investigate the mysterious death of Lannis Cadogan.

Mystical properties
The millhouse is known to be larger on the inside, which is not only explained by spacious, several stores high cellar, but also doors with endless corridors accessible.

It also has some magical security measures to keep both the inhabitants and the artifacts safe, including a zero gravity trap.

Owners

 * Jasper Winters (deceased)
 * Liv Aberdine (left John Constantine to operate and keep)
 * John Constantine (housekeeper)

Residents

 * Chas Chandler
 * Zed Martin

Visitors

 * Gary Lester (deceased)
 * Manny

Objects storaged
Millhouse is known to house large amounts of mystical artifacts and related accessories including:
 * A large number of custom maps and globes
 * Assorted books on magic, demonology and mysticism
 * An old television set
 * Skull-shaped box
 * Golden helmet
 * Black diamond
 * Egyptian staff
 * Ring of Solomon
 * Zootrope
 * Sword of Night
 * Golden mask
 * Imogen's heart

Trivia

 * Millhouse being larger on the inside is a reference to TARDIS from Doctor Who television series.
 * It is not the only reference to the series in Constantine as John also posesses a magical Six of Diamonds card which is very similar in its functions to Psychic paper from Doctor Who.

Behind the scenes

 * In the DC comics Baron Winter's residence, Wintersgate Manor functions as a veritable gateway to different locations and time periods, which is directly referenced when Zed Martin opens the door which leads to an endless corridor. Wintersgate Manor, just as the millhouse also serves for a supernatural vigilante/superhero team, Night Force, led by Winters. John Constantine was not a member of the team, but crossed the paths with them and their leader on multiple occassions.
 * Another similar mansion in DC comics House of Mystery which John Constantine used for a while as his main base of operations in the current DC continuity. Millhouse shares a few similarities with the House of Mystery, including an assortment