---
url: /academy-handbook/foundation/week-2/index.md
---
# Week 2 — Blockchain architectures, Ethereum and interoperability

  

> **Core question — why are there many different blockchains, and how do they
> connect?**

Week 1 taught you what a blockchain is, using Ethereum as the example. That
leaves an obvious question: if this works, why are there thousands of them, and
why do they keep making different choices?

**Because there is no single best design — only trade-offs.** This week teaches
you to see them, which is the skill that lets you evaluate any network you meet
from here on.

| Part | Page | Reading |
|---|---|---|
| 1 | [Public, private and consortium chains](./part-1-access-models.md) | 20 min |
| 2 | [Comparing blockchains and their trade-offs](./part-2-comparing-blockchains.md) | 25 min |
| 3 | [Why we start with Ethereum and the EVM](./part-3-why-ethereum-and-evm.md) | 20 min |
| 4 | [Transactions, state, gas and RPC](./part-4-transactions-and-gas.md) | 25 min |
| 5 | [L1, L2, sidechains and bridges](./part-5-l1-l2-and-bridges.md) | 30 min |
| 6 | [The trust and risk map](./part-6-trust-and-risk-map.md) | 15 min |

**Anchor Mission:** [Week 2 mission](./anchor-mission.md) · 100 points

## The arc

```mermaid
flowchart TD
  P1["<b>1 · Access models</b><br/><i>who is allowed to participate?</i>"]
  P2["<b>2 · Comparing chains</b><br/><i>what do they trade away?</i>"]
  P3["<b>3 · Ethereum and the EVM</b><br/><i>why do we start here?</i>"]
  P4["<b>4 · Transactions, gas and RPC</b><br/><i>how does it actually run?</i>"]
  P5["<b>5 · L1, L2 and bridges</b><br/><i>how do networks connect?</i>"]
  P6["<b>6 · Trust and risk map</b><br/><i>who am I trusting, at each step?</i>"]
  P1 --> P2 --> P3 --> P4 --> P5 --> P6
```

::: important Part 6 is the shortest page and the one the rest of the Foundation leans on hardest
Give it proper attention.
:::

## What this week is not

This week is **analytical, not technical**. No wallet work and no code — that
returns in Week 3.

Depth is deliberately capped. Bridge verification mechanisms, modular
architecture, data availability layers and ZK internals are **Further
Exploration**, not Core. You are building a map, not mastering a subfield.