Bitcoin Timechain Milestones: Key Blocks and Events

Bitcoin Timechain Milestones Overview

Bitcoin's blockchain (often called the "timechain" in reference to Satoshi Nakamoto's original terminology) is a continuously growing ledger of every transaction since January 3, 2009. Certain blocks stand out as turning points: protocol upgrades, economic shifts, cultural moments, and technical firsts. This reference catalogs those milestones with verified block numbers, dates, and context.

The following table summarizes every major milestone in Bitcoin's history. Each event is covered in detail in the sections below.

Use the block-by-date lookup tool to find which block was mined on any specific date, or the halving countdown to track progress toward the next reward reduction.

The Genesis Block and Early Network

Block 0, the genesis block, was mined by Satoshi Nakamoto on January 3, 2009 at 18:15:05 UTC. Its coinbase transaction contains the hex-encoded message: "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks." This served two purposes: a timestamp proof that the block could not have been created before that date, and a commentary on the 2008 financial crisis that motivated Bitcoin's creation.

Block 1 was not mined until January 9, 2009, a six-day gap. The delay likely coincides with Satoshi releasing the Bitcoin client (v0.1) on that date. The genesis block's 50 BTC reward is unspendable due to a quirk in the original code: the genesis coinbase transaction was not added to the transaction database.

Block 170 (January 12, 2009) contains the first peer-to-peer Bitcoin transaction: Satoshi sent 10 BTC to Hal Finney, a cryptographer who was the first person other than Satoshi to run the Bitcoin software. This transaction (txid f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16) proved that the payment network functioned as designed.

Halving Events

Every 210,000 blocks, the block subsidy paid to miners is cut in half. This mechanism enforces Bitcoin's fixed supply schedule: 21 million coins total, with the last satoshi expected to be mined around 2140. Each halving reduces the rate of new supply entering circulation, a deflationary pressure that has historically preceded major price appreciation cycles.

By the fourth halving in April 2024, over 93% of all bitcoin that will ever exist had already been mined. The 20 millionth BTC was mined on March 9, 2026. For a deeper analysis of how halvings affect miner economics and network security, see our research on Bitcoin halving economics and the fee market dynamics that become increasingly important as block subsidies diminish.

Protocol Upgrades

Bitcoin's consensus rules have evolved through carefully coordinated soft forks. Unlike hard forks (which split the chain), soft forks are backward-compatible: older nodes continue to accept blocks produced under the new rules.

SegWit: Block 481,824

Segregated Witness activated on August 24, 2017 at block 481,824, mined by BTCC. SegWit separated witness data (signatures) from the base transaction, fixing the long-standing transaction malleability bug that had blocked second-layer protocols. It also introduced a new weight-based block size metric, effectively increasing capacity from 1 MB to roughly 4 MB (in virtual bytes). SegWit was locked in on August 9, 2017 after achieving the required signaling threshold between blocks 477,792 and 479,807.

SegWit was a prerequisite for the Lightning Network. Without fixing transaction malleability, payment channels could not operate securely. For details on how Lightning leverages SegWit transactions, see our research on payment channels from concept to implementation.

Taproot: Block 709,632

Taproot activated on November 14, 2021 at block 709,632. This upgrade bundled three BIPs: BIP 340 (Schnorr signatures), BIP 341 (Taproot script structure), and BIP 342 (Tapscript validation). Schnorr signatures enable key and signature aggregation, making multisig transactions indistinguishable from single-sig on-chain. This improves both privacy and efficiency.

Taproot also expanded Bitcoin's scripting capabilities, enabling more complex spending conditions while keeping the common case (a simple key spend) compact and cheap. The upgrade laid groundwork for protocols like Ordinals and Runes, which leverage Taproot's expanded witness space. For a technical deep dive, see our Taproot and Schnorr signatures explainer.

Bitcoin Cash Fork: Block 478,558

Block 478,558 (August 1, 2017) was the last block shared by Bitcoin and Bitcoin Cash. The fork was driven by disagreements over scaling strategy: Bitcoin Cash proponents favored larger blocks (8 MB initially) over SegWit. The first Bitcoin Cash block (478,559) was mined by ViaBTC approximately six hours after the split. This remains the most significant chain split in Bitcoin's history.

Notable Blocks and Transactions

Bitcoin Pizza Day: Block 57,043

On May 22, 2010, developer Laszlo Hanyecz sent 10,000 BTC to Jeremy Sturdivant in exchange for two Papa John's pizzas. This was the first documented commercial Bitcoin transaction. The 10,000 BTC was worth approximately $41 at the time. Hanyecz, who also pioneered GPU mining, posted the original offer on the BitcoinTalk forum. May 22 is now celebrated annually as Bitcoin Pizza Day.

First Ordinals Inscription: Block 767,430

On December 14, 2022, Casey Rodarmor inscribed a pixel art skull as inscription #0 on Bitcoin mainnet. This was 36 days before he publicly announced that Ordinals inscriptions were ready for mainnet use. Ordinals assign a serial number to each satoshi based on the order it was mined, enabling NFT-like artifacts directly on Bitcoin's base layer without requiring a sidechain or separate token. The BRC-20 token standard followed in March 2023, built on top of the Ordinals protocol.

Taproot Wizard: Block 774,628

On February 1, 2023, Luxor Mining produced a 3.96 MB block containing the "Taproot Wizard" inscription: a large pixel art image that comprised 99.5% of the block's total size. Created by developer Udi Wertheimer in collaboration with Luxor CEO Nick Hansen, this block pushed close to the theoretical maximum block weight under SegWit's 4 million weight unit limit. It demonstrated both the capacity of Taproot witness data and sparked debate about block space usage.

Block 666,666: The Biblical Message

On January 18, 2021, a user embedded the message "Do not be overcome by evil, but overcome evil with good" (Romans 12:21) in block 666,666 by sending 0.01 BTC each to two vanity addresses starting with "1GoD" and "1BibLE." The sender paid approximately $50 in fees (5x the average) to ensure the transaction was included in this symbolically significant block. This is one of many examples of messages embedded in Bitcoin's OP_RETURN and address-based data throughout the chain's history.

Round-Number Milestones

The difficulty adjustment mechanism keeps blocks arriving at roughly one every 10 minutes, recalibrating every 2,016 blocks (approximately two weeks). This predictable cadence makes future block dates estimable. Use the block-by-date tool to convert between block heights and calendar dates.

Satoshi's Mining Activity

Blockchain researchers have identified a distinctive mining pattern (the "Patoshi pattern") attributed to Satoshi Nakamoto. This miner was active from block 0 through approximately block 54,316 (May 2010), accumulating an estimated 1,125,150 BTC. None of these coins have ever moved. Satoshi's last known public communication to Bitcoin developers was on April 23, 2011, and the Patoshi miner was systematically wound down over the preceding year.

The Runes Protocol: Block 840,000

The fourth halving block also marked the launch of the Runes protocol, created by Casey Rodarmor (the same developer behind Ordinals). Runes enables fungible token issuance directly on Bitcoin using the UTXO model, unlike BRC-20 tokens which rely on off-chain indexing of inscription data. The first rune ("UNCOMMON GOODS," rune 0) was minted at block 840,000. This represented a shift in how developers thought about tokenization on Bitcoin, moving beyond the inscription model toward a more UTXO-native approach.

For more on how tokens and assets are issued on Bitcoin, including layer-2 approaches like Spark, see our research on stablecoins on Bitcoin.

Frequently Asked Questions

What was the first Bitcoin block?

The first Bitcoin block is block 0, known as the genesis block. It was mined by Satoshi Nakamoto on January 3, 2009 at 18:15:05 UTC. The block's coinbase transaction contains the embedded text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks," referencing a headline from The Times newspaper. The genesis block's 50 BTC reward is unspendable due to a quirk in the original Bitcoin code.

When was the first Bitcoin transaction?

The first peer-to-peer Bitcoin transaction occurred in block 170 on January 12, 2009. Satoshi Nakamoto sent 10 BTC to Hal Finney, a cryptographer and early Bitcoin contributor. This transaction demonstrated that the peer-to-peer electronic cash system described in the Bitcoin whitepaper worked as intended.

How many Bitcoin halvings have there been?

As of 2026, there have been four halvings: block 210,000 (November 2012), block 420,000 (July 2016), block 630,000 (May 2020), and block 840,000 (April 2024). The block subsidy has decreased from 50 BTC to 3.125 BTC per block. The fifth halving is estimated around March 2028 at block 1,050,000, reducing the reward to 1.5625 BTC. Track the countdown with the halving countdown tool.

What block activated SegWit on Bitcoin?

SegWit activated at block 481,824 on August 24, 2017. The upgrade separated witness data from transaction data, fixing transaction malleability and increasing effective block capacity. SegWit was a soft fork, meaning it was backward-compatible with older nodes. It was also a prerequisite for the Lightning Network, which relies on non-malleable transaction IDs for secure payment channel operation.

What block activated Taproot?

Taproot activated at block 709,632 on November 14, 2021. The upgrade introduced Schnorr signatures, improved smart contract capabilities via Tapscript, and enhanced on-chain privacy by making complex spending conditions indistinguishable from simple key spends. Taproot's expanded witness space later enabled the Ordinals and Runes protocols.

What was the Bitcoin Pizza Day transaction?

On May 22, 2010, Laszlo Hanyecz paid 10,000 BTC for two Papa John's pizzas in block 57,043. This was the first known commercial Bitcoin transaction, valuing the 10,000 BTC at roughly $41. The event is celebrated annually as Bitcoin Pizza Day and serves as a benchmark for how much purchasing power early BTC has gained over time.

When will all 21 million Bitcoin be mined?

The last satoshi is expected to be mined around the year 2140. As of March 2026, over 20 million BTC (approximately 95.2% of the total supply) had already been mined. Each halving progressively slows the rate of new issuance: the current block subsidy of 3.125 BTC means only about 164,250 new BTC are created per year. After the final coin is mined, miners will rely entirely on transaction fees for revenue. See our analysis of the mining economics driving this transition.

This reference is for informational purposes only and does not constitute financial advice. Block numbers and dates are based on publicly available blockchain data. Estimated future dates (fifth halving, block 1,000,000) depend on network hashrate and difficulty adjustments. Always verify block data using a block explorer for time-sensitive decisions.