Play Glacial Chasm either from your hand or from your graveyard.
When Glacial Chasm enters the battlefield, its second ability triggers, causing you to sacrifice another land you control.
Play any land from your graveyard.
At the beginning of your next upkeep, Glacial Chasm's cumulative upkeep ability triggers, allowing you to choose not to pay the cost and sacrifice it instead.
Repeat.

Prevent all damage that would be dealt to you

Lock

Glacial Chasm

Ramunap Excavator

Dryad of the Ilysian Grove

Play Simic Growth Chamber. When it enters untapped due to Spelunking, Simic Growth Chamber and Springheart Nantuko trigger.
Holding priority, activate Simic Growth Chamber by tapping it, adding {G}{U}.
Resolve the Simic Growth Chamber trigger, returning it from the battlefield to your hand.
Resolve the Springheart Nantuko trigger, causing you to pay {1}{G} to create a token copy of Dryad of the Ilysian Grove.
Because of the additional Dryad of the Ilysian Grove token, you can play an additional land this turn. 
Repeat.

Infinite creature tokens

Infinite landfall triggers

Infinite creature ETB

Infinite blue mana

Infinite card draw

Infinite draw triggers

Infinite green mana

Springheart Nantuko

Spelunking

Simic Growth Chamber

Play Gruul Turf. When it enters, Amulet of Vigor, Gruul Turf and Springheart Nantuko trigger.
Resolve the Amulet of Vigor trigger, untapping Gruul Turf.
Holding priority, activate Gruul Turf by tapping it, adding {R}{G}.
Resolve the Gruul Turf trigger, returning it from the battlefield to your hand.
Resolve the Springheart Nantuko trigger, causing you to pay {1}{G} to create a token copy of Dryad of the Ilysian Grove.
Because of the additional Dryad of the Ilysian Grove token, you can play an additional land this turn. 
Repeat.

Gruul Turf

Amulet of Vigor

Play Simic Growth Chamber.
Return Simic Growth Chamber to your hand using its enter the battlefield trigger.
Emeria Shepherd triggers, targeting Uro.
Uro returns from your graveyard to the battlefield.
Stack Uro triggers so Uro is sacrificed first, then draw a card and play Simic Growth Chamber.
Repeat steps 2-5.

Infinite death triggers

Infinite lifegain

Infinite lifegain triggers

Infinite creature LTB

Put all lands from your library onto the battlefield

Near-infinite lifegain

Near-infinite lifegain triggers

Uro, Titan of Nature's Wrath

Emeria Shepherd

Activate Phyrexian Altar by sacrificing Dryad Arbor, adding one mana of any color.
Dryad Arbor dies, triggering Abduction, returning Dryad Arbor to the battlefield.
Emeria Shepherd triggers, returning Abduction to the battlefield enchanting Dryad Arbor.
Repeat.

Combos with "Dryad of the Ilysian Grove"